OFFICE OF THE FEDERAL COORDINATOR FOR 

METEOROLOGICAL SERVICES AND SUPPORTING RESEARCH 

U.S. DEPARTMENT OF COMMERCE/ National Oceanic and Atmospheric Administration 

Washington, DC

May 2017 

National Hurricane 

Operations Plan 

FCM-P12-2017 
Front cover: Hurricane Matthew at 2115 GMT September 30, 2016, undergoing rapid 

intensification on the way to becoming the first Category 5 Atlantic storm in more than nine 

years and the southernmost Category 5 storm on record (28 miles south of Hurricane Ivan). 

Matthew intensified from a tropical storm at 1500 GMT on September 29th to Category 5 at 

0300 GMT on October 1st, with the sustained winds increasing from 70 to 160 mph and the 

central pressure decreasing from 996 to 941 hPa. Image courtesy of NASA/NOAA GOES 

Project.
FEDERAL COORDINATOR

FOR

METEOROLOGICAL SERVICES AND SUPPORTING 

RESEARCH

1325 East-West Highway, SSMC2

Silver Spring, Maryland 20910 

301-628-0112

http://www.ofcm.gov/

NATIONAL HURRICANE OPERATIONS 

PLAN

http://www.ofcm.gov/publications/nhop/FCM-P12-2017.pdf

FCM-P12-2017

Washington, D.C.

May 2017
ii

CHANGE AND REVIEW LOG

Use this page to record changes and notices of reviews.

Change

Number

Page Numbers Date Posted

(mm/dd/yyyy)

Initials

1. I-2, L-1 5/4/2017 JS

2.

3.

4.

5.

Changes are indicated by a vertical line in the margin next to the change or by shading and 

strikeouts.

No. Review Date

(mm/dd/yyyy)

Comments Initials

1.

2.

3.

4.

5.
iii

FOREWORD

The Office of the Federal Coordinator for Meteorological Services and Supporting Research 

(OFCM) works with Federal agency stakeholders to plan hurricane observing and 

reconnaissance in preparation for each hurricane season. OFCM’s Working Group for Hurricane 

and Winter Storms Operations and Research (WG/HWSOR) manages the process of publishing 

an annual update to the National Hurricane Operations Plan (NHOP), which documents the

agreed-upon interagency plans.

The NHOP focuses heavily on the planning, execution, and use of aerial reconnaissance 

conducted by the Air Force Reserve Command’s 53rd Weather Reconnaissance Squadron and 

NOAA’s Aircraft Operations Center, but also addresses meteorological satellite, weather radar, 

and ocean observing as well as a number of other related topics.

The 2017 NHOP includes a number of noteworthy changes, including:

• Updated the plan with actual operational practices and areas of warning responsibility in the 

Pacific basin (sections 2.2.2, 3.2.1, 7.2.2.2, and A.2.1).

• Revised tropical cyclone names and pronunciations (Tables 3-2 through 3-5).

• Updated information on the Tropical Cyclone Watch Warning Product (TCV) (section 3.2.8).

• Added communications headings for aerial reconnaissance messages (section 5.7, Table 5-3, 

Figure 5-8).

• Updated Mission Coordination Sheet used in weather reconnaissance missions (Appendix L).

• Improved overall organization and extensively updated message codes (HDOB and RECCO)

and data formats in Appendix G (sections G.1 and G.2, Figures G-1, G-3 and G-6, Tables G1 through G-7).

• Renamed and extensively updated Chapter 6 reflecting new procedures including designation 

of Weather Reconnaissance Airspace (WRA); revised Appendix F to replace agreements 

supporting the changes to Chapter 6 including WRA procedures.

• Updated meteorological satellite information (Chapter 7).

• Added new NEXRAD Tropical Cyclone Operations Plan for 2017 (section 8.3).

• Added information on deployment of airborne expendable bathythermographs (Chapter 9).

Thanks to all the participating Federal agencies for their cooperation in reviewing last year’s 

NHOP, identifying and drafting necessary changes, and working together to approve and 

incorporate those changes into the 2017 NHOP. Thanks also to Dr. Daniel Melendez for 

coordinating the efforts of WG/HWSOR and editing the new plan, and to Ms. Erin McNamara 

improving the formatting and publishing the plan on the OFCM Web site.

//SIGNED//

Dr. William J. Schulz

Federal Coordinator for Meteorological 

Services and Supporting Research
iv
v

NATIONAL HURRICANE OPERATIONS PLAN

TABLE OF CONTENTS

Page

CHANGE AND REVIEW LOG ii

FOREWORD iii

TABLE OF CONTENTS v

CHAPTER 1 INTRODUCTION 1-1

1.1. General 1-1

1.2. Scope 1-1

CHAPTER 2 RESPONSIBILITIES OF COOPERATING FEDERAL

AGENCIES 2-1

2.1. General 2-1

2.2. DOC Responsibilities 2-1

2.3. DOD Responsibilities 2-3

2.4. DOT and DHS Responsibilities 2-4

2.5. Annual Liaison with Other Nations 2-4

2.6. Air Traffic Control/Flight Operations Coordination 2-5

CHAPTER 3 GENERAL OPERATIONS AND PROCEDURES OF THE NATIONAL 

WEATHER SERVICE HURRICANE CENTERS 3-1

3.1. General 3-1

3.2. Products 3-1

3.3. Numbering and Naming of Tropical and Subtropical Cyclones 3-4

3.4. Transfer of Warning Responsibility 3-6

3.5. Alternate Warning Responsibilities 3-6

3.6. Abbreviated Communications Headings 3-11

3.7. Hurricane Liaison Team (HLT) 3-13

CHAPTER 4 NATIONAL WEATHER SERVICE PRODUCTS FOR THE 

DEPARTMENT OF DEFENSE 4-1

4.1. General 4-1

4.2. Observations 4-1

4.3. Tropical Cyclone Forecast/Advisory 4-1

CHAPTER 5 AIRCRAFT RECONNAISSANCE 5-1

5.1. General 5-1
vi

5.2. Responsibilities 5-1

5.3. Control of Aircraft 5-2

5.4. Reconnaissance Requirements 5-2

5.5. Reconnaissance Planning and Flight Notification 5-5

5.6. Reconnaissance Effectiveness Criteria 5-13

5.7. Aerial Reconnaissance Weather Encoding, Reporting, and 

Coordination 5-15

5.8. Operational Flight Patterns 5-19

5.9. Aircraft Reconnaissance Communications 5-22

CHAPTER 6 AIRCRAFT OPERATIONS 6-1

6.1. Mission Coordination 6-1

6.2. Mission Execution 6-5

CHAPTER 7 SATELLITE SURVEILLANCE OF TROPICAL AND SUBTROPICAL 

CYCLONES 7-1

7.1. Satellites 7-1

7.2. National Weather Service (NWS) Support 7-7

7.3. NESDIS Satellite Analysis Branch (SAB) 7-7

7.4. Air Force Support and the Defense Meteorological Satellite Program 

(DMSP) 7-8

7.5. Satellites and Satellite Data Availability for the Current Hurricane 

Season 7-8

7.6. Current Intensity and Tropical Classification Number Using the 

Dvorak Technique 7-8

CHAPTER 8 SURFACE RADAR REPORTING 8-1

8.1. General 8-1

8.2. The WSR-88D 8-1

8.3. Procedures 8-1

CHAPTER 9 NATIONAL DATA BUOY CAPABILITIES AND

REQUIREMENTS 9-1

9.1. General 9-1

9.2. Requests for Drifting Buoy Deployment 9-2

9.3. Communications 9-2

CHAPTER 10 MARINE WEATHER BROADCASTS 10-1

10.1. General 10-1

10.2. Global Maritime Distress and Safety System (GMDSS) 10-1
vii

10.3. Coastal Maritime Safety Broadcasts 10-1

10.4. High Seas Broadcasts 10-2

10.5. Additional Information 10-3

CHAPTER 11 PUBLICITY 11-1

11.1. News Media Releases 11-1

11.2. Distribution 11-1
viii

APPENDIX A LOCAL NATIONAL WEATHER SERVICE (NWS) OFFICE 

PRODUCTS A-1

APPENDIX B DEFINING POINTS FOR TROPICAL CYCLONE WATCHES/ 

WARNINGS B-1

APPENDIX C JOINT TYPHOON WARNING CENTER (JTWC) BULLETINS C-1

APPENDIX D FORMAT FOR NHOP/NWSOP FLIGHT INFORMATION FOR 

INTERNATIONAL AND DOMESTIC NOTAM ISSUANCE D-1

APPENDIX E SAFFIRSIMPSON HURRICANE WIND SCALE E-1

APPENDIX F OFFICIAL INTERAGENCY AGREEMENTS F-1

APPENDIX G RECCO, HDOB, AND TEMP DROP CODES, TABLES, AND 

REGULATIONS G-1

APPENDIX H RESERVED H-1 

APPENDIX I TELEPHONE LISTING I-1

APPENDIX J GEOGRAPHICAL DEFINING POINTS AND PHONETIC 

PRONUNCIATION J-1

APPENDIX K NHOP OPERATIONAL MAPS (TERMINAL AREAS) K-1

APPENDIX L MISSION COORDINATION SHEET L-1

APPENDIX M ACRONYMS/ABBREVIATIONS M-1

APPENDIX N GLOSSARY N-1
ix

LIST OF FIGURES

Figure Page

1-1. Tropical Cyclone Forecast Centers' Areas of Responsibility 1-2

4-1. Tropical Cyclone Forecast/Advisory Format 4-4

4-2. Tropical Cyclone Public Advisory Format 4-5

5-1. WC-130J Weather Reconnaissance Aircraft 5-2

5-2. NOAA G-IV and WP-3D Weather Surveillance/Hurricane Aircraft 5-2

5-3. Vortex Data Message Worksheet 5-6

5-4. Example Vortex Data Message (VDM) for the WC-130J 5-9

5-5. NHOP Coordinated Request for Aircraft Reconnaissance 5-10

5-6. Tropical Cyclone Plan of the Day Format 5-11

5-7. Mission Evaluation Form 5-15

5-8. Geographical Basins in Aerial Reconnaissance Abbreviated Headings 5-18

5-9. Flight Pattern ALPHA 5-20

5-10. Suggested Patterns for Investigative Missions 5-21

5-11. Schematic of WMO Message Path for NOAA G-IV and P-3 Aircraft 5-23

5-12. Schematic of Aircraft-to-Satellite Data Link for AFRC WC-130 Aircraft 5-24

7-1. The GOES Satellite System 7-5

9-1. Example Buoy and Float Deployment Pattern 9-3

G-1. Example USAF and NOAA Aircraft RECCO Messages for Tropical Cyclones G-1

G-2. Reconnaissance Code Recording Form G-5

G-3 Geographical Depiction of Octants Encoded in RECCO Messages G-9

G-4. Example HDOB Message for Tropical Cyclones G-10

G-5. Example TEMP DROP Message for Tropical Cyclones G-14

G-6 Marsden Square Reference Diagram G-20

K-1. Texas Coast K-1

K-2. Lake Charles, LA – Pensacola, FL K-2

K-3. Pensacola, FL – Tallahassee, FL K-3

K-4. Central/Southern Florida K-4

K-5. Cuba – Grand Cayman K-5

K-6. The Bahamas: Nassau - Freeport K-6

K-7. Turks & Caicos Islands: Grand Turk - Providenciales K-7

K-8. Daytona Beach, FL – Myrtle Beach, SC K-8
x

K-9. Wilmington, DE – Atlantic City, NJ K-9

K-10 Radar coverage map – San Juan, PR, Air Route Traffic Control Center. K-10

K-11 Radar coverage map – Miami, FL, Air Route Traffic Control Center. K-11
xi

LIST OF TABLES

Table Page

3-1. Primary and alternate operational warning responsibilities 3-7

3-2. Atlantic Tropical Cyclone Names 3-8

3-3. Eastern Pacific Tropical Cyclone Names 3-9

3-4. Central Pacific Tropical Cyclone Names 3-10

3-5. International Tropical Cyclone Names for the Northwest Pacific and South

China Sea 3-11

3-6. Summary of Products and their Associated WMO Header 3-12

5-1. Requirements for Aircraft Reconnaissance Data 5-5

5-2. Vortex Data Message Entry Explanation 5-7

5-3. Summary of Aerial Reconnaissance Data Products and their Associated 

Headers 5-17

5-4. Elements of the Mission Identifier 5-18

5-5. Examples of Corrected Observations 5-19

7-1. Communications Headings for SAB Dvorak Analysis Products 7-8

7-2. Satellite and Satellite Data Availability for the Current Hurricane Season 7-9

7-3. The Dvorak Technique: The Empirical Relationship between the C.I. Number 

and the Maximum Wind Speed and the Relationship between the T-Number 

and the Minimum Sea-Level Pressure (SLP) 7-12

8-1. Participating WSR-88D Radar Stations 8-2

G-l. Decoded USAF Aircraft RECCO Message G-2

G-2. Decoded NOAA Aircraft RECCO Message G-4

G-3. Reconnaissance Code Tables G-6

G-4. Reconnaissance Code Regulations G-8

G-5. Mission/Ob Identifier Line Format for HDOB Messages G-10

G-6. HD/HA Data Line Format for HDOB Messages G-11

G-7 TEMP DROP CODE G-15
xii
1-1

CHAPTER 1: INTRODUCTION

1.1 General.

The tropical cyclone warning service is an interdepartmental effort to provide the United States 

and designated international recipients with forecasts, warnings, and assessments concerning 

tropical and subtropical weather systems. The National Oceanic and Atmospheric Administration 

(NOAA) of the Department of Commerce (DOC) is responsible for providing forecasts and 

warnings for the Atlantic and Eastern and Central Pacific Oceans while the Department of 

Defense (DOD) provides the same services for the Western Pacific and Indian Ocean (see Figure 

1-1). NOAA, along with other Federal agencies such as the U.S. Navy and the National 

Aeronautics and Space Administration (NASA), also conducts supporting research efforts to

improve tropical cyclone forecasting and warning services. The bottom line—this

interdepartmental cooperation achieves economy and efficiency in the provision of the tropical 

cyclone forecasting and warning services to the Nation. The National Hurricane Operations 

Plan provides the basis for implementing agreements reached at the Interdepartmental Hurricane 

Conference (IHC), which is sponsored annually by the Office of the Federal Coordinator for 

Meteorological Services and Supporting Research. The goal of the IHC is to bring together the 

responsible Federal agencies to achieve agreement on items of mutual concern related to tropical 

cyclone forecasting and warning services for the Atlantic and Pacific Oceans.

1.2 Scope.

The procedures and agreements contained herein apply to the Atlantic Ocean, Gulf of Mexico, 

Caribbean Sea, and the Pacific Ocean. The plan defines the roles of individual agencies,

participating in the tropical cyclone forecasting and warning program when more than one 

agency is involved in the delivery of service in any specific area. When a single agency is 

involved in any specific area, that agency's procedures should be contained in internal documents 

and, to the extent possible, be consistent with NHOP practices and procedures.
1-2

Figure 1-1. Tropical Cyclone Forecast Centers' Areas of Responsibility
2-1

CHAPTER 2: RESPONSIBILITIES OF COOPERATING 

FEDERAL AGENCIES

2.1. General. 

The Department of Commerce (DOC), through the National Oceanic and Atmospheric 

Administration (NOAA), is charged with the overall responsibility to implement a responsive, 

effective national tropical cyclone warning service. Many local, state, and Federal agencies play 

a vital role in this system; their cooperative efforts help ensure that necessary preparedness 

actions are taken to minimize loss of life and destruction of property. The joint participation by 

the Department of Defense (DOD), the Department of Transportation (DOT), and the 

Department of Homeland Security (DHS)/U.S. Coast Guard (USCG) with the DOC brings to 

bear those Federal resources considered essential for storm detection and accurate forecasting. 

This cooperative effort has proven to be a cost-effective, highly responsive endeavor to meet 

national requirements for tropical cyclone warning information.

2.2. DOC Responsibilities.

2.2.1. Forecasting and Warning Services. 

The DOC will provide timely dissemination of forecasts, warnings, and all significant 

information regarding tropical and subtropical cyclones to the appropriate agencies, marine and 

aviation interests, and the general public.

2.2.2. Support to DOD. 

Through NOAA's National Weather Service (NWS), the DOC will:

• Consult, as necessary, with the DOD regarding their day-to-day requirements for 

forecast/advisory services and attempt to meet these requirements within the capabilities of 

the tropical cyclone warning service.

• Provide, through the National Hurricane Center (NHC), the coordinated DOC requirements 

for weather reconnaissance and other meteorological data to be acquired by the DOD on 

tropical or subtropical cyclones and disturbances.

• Provide facilities, administrative support, and the means to disseminate meteorological data 

for the Chief, Aerial Reconnaissance Coordination, All Hurricanes (CARCAH) as agreed to 

by the DOC and DOD.

• Provide the DOD with basic meteorological information, warnings, forecasts, and associated 

prognostic reasoning concerning location, intensity, and forecast movement of tropical and 

subtropical cyclones in the following maritime areas, including the adjacent states and 

possessions of the United States:

• Atlantic Ocean (north of the equator including the Caribbean Sea and Gulf of Mexico). 

Advisories are the responsibility of the Director, NHC, Miami, FL. The NHC will consult 

with the Fleet Weather Center, Norfolk, VA, prior to issuing initial and final advisories 

and prior to issuing any advisory that indicates a significant change in forecast of 
2-2

intensity or track from the previous advisory. Exchange of information is encouraged on 

subsequent warnings when significant changes are made or otherwise required.

• Eastern Pacific Ocean (north of the equator and east of 140°W). Advisories are the 

responsibility of the Director, NHC, Miami, FL. The NHC will consult with the Joint 

Typhoon Warning Center (JTWC), Pearl Harbor, HI, prior to issuing initial and final 

advisories and prior to issuing any advisory that indicates a significant change in forecast 

of intensity or track from the previous advisory. Exchange of information is encouraged 

on subsequent warnings when significant changes are made or otherwise required. The 

NHC will notify JTWC prior to issuance of a Special Tropical Weather Outlook (TWO).

• Central Pacific Ocean (north of the equator between 140°W and 180°). Advisories are the 

responsibility of the Director, Central Pacific Hurricane Center (CPHC), Honolulu, HI. In 

addition to the main Hawaiian Islands, CPHC also issues watches and warnings for 

Johnston Atoll, Palmyra Atoll, Midway, and the northwest Hawaiian Islands. The CPHC 

will consult with JTWC prior to issuing initial and final advisories and prior to issuing 

any advisory that indicates a significant change in forecast of intensity or track from the 

previous advisory. Exchange of information is encouraged on subsequent warnings when 

significant changes are made or otherwise required. The CPHC will notify JTWC prior to 

issuance of a Special Tropical Weather Outlook (TWO).

• West Pacific Ocean (Guam and Micronesia). Public advisories are prepared by the NWS 

Weather Forecast Office (WFO) Guam, using the tropical cyclone forecasts/advisories 

prepared by JTWC as guidance. WFO Guam issues watches and warnings for all tropical 

cyclones affecting the Territory of Guam, the Commonwealth of the Northern Marianas, 

the Republic of Palau, the Federated States of Micronesia, and the Republic of the 

Marshall Islands.

2.2.3. Post Analysis of Tropical Cyclones. 

The DOC, through NWS, will conduct an annual post analysis for all tropical cyclones in the 

Atlantic and the Pacific regions east of 180° and prepare an annual hurricane report for issue to 

interested agencies.

2.2.4. Environmental Satellite Systems. 

The National Environmental Satellite, Data, and Information Service (NESDIS) will:

• Operate DOC environmental satellite systems capable of providing coverage of 

meteorological conditions in the tropics during the tropical cyclone season, and monitor and 

interpret DOC satellite imagery.

• Obtain, as necessary, National Aeronautics and Space Administration (NASA) research and 

development satellite data and Defense Meteorological Satellite Program (DMSP) data for 

NWS operational use and to comply with NHC and CPHC satellite data requirements.

• Provide surveillance support with fixes and/or intensity estimates to the Joint Typhoon 

Warning Center (JTWC), NHC, and CPHC through analysis of all available satellite 

imagery.
2-3

2.2.5. Data Buoy Systems. 

Through the National Data Buoy Center (NDBC), the DOC will, subject to available funding, 

develop, deploy, and operate environmental data buoy systems and automated coastal stations to 

support the data requirements of NHC and CPHC.

2.2.6. Weather Reconnaissance. 

Through the NOAA Office of Marine and Aviation Operations (OMAO), DOC will provide 

weather reconnaissance flights, including synoptic surveillance, as specified in Chapter 5, unless 

relieved of these responsibilities by the Administrator of NOAA.

2.3. DOD Responsibilities. 

The DOD will:

• Disseminate significant meteorological information on tropical and subtropical cyclones to 

the NWS in a timely manner.

• Provide NHC and CPHC current DOD requirements for tropical and subtropical cyclone 

advisories.

• Meet DOC requirements for aircraft reconnaissance and other special observations.

• Provide at NHC a 24-hour aircraft operations interface—Chief, Aerial Reconnaissance 

Coordination, All Hurricanes (CARCAH).

• Designate CARCAH as the liaison to NHC. CARCAH will serve as NHC's point of contact 

to request special DOD observations in support of this plan (e.g., additional upper-air 

observations).

• Provide weather reconnaissance data monitor services to evaluate and disseminate 

reconnaissance reports.

• Provide surveillance support with fixes and/or intensity estimates to the Central Pacific 

Hurricane Center through analysis of available satellite imagery. The support is provided by 

the 17th Operational Weather Squadron Meteorological Satellite Operations (SATOPS) 

Flight (17 OWS/WXJ), Joint Typhoon Warning Center, Pearl Harbor, HI, and is focused on 

the Indian Ocean and the Central, South, and Northwest Pacific Ocean.

• Western Pacific Ocean (north of the equator): Provide NWS with basic meteorological 

information, forecasts, and associated prognostic reasoning, concerning location, intensity, 

wind distribution, and forecast movement of tropical cyclones for the Northwest Pacific west 

of 180o

. JTWC will consult with WFO Guam regarding all tropical cyclones affecting 

Micronesia and Guam. Consultation will occur prior to issuing initial and final advisories and 

prior to issuing any advisory that indicates a significant change in forecast intensity or track 

from the previous advisory.

• Initiate, monitor, and update satellite invest areas on the tropical cyclone satellite websites 

provided by the Fleet Numerical Meteorology and Oceanography Center (FNMOC) and the 

Naval Research Laboratory (NRL), Monterey, California. NHC and CPHC will coordinate 

with JTWC on the initiation of desired invest areas and will provide JTWC numbers for 

invest areas as required.

• Deploy, through the Naval Oceanographic Office (NAVOCEANO), drifting data buoys in 

support of the Commander, U.S. Atlantic Fleet (COMLANTFLT) requirements.
2-4

• At a minimum, maintain situation awareness of hurricane hunter operational missions 

conducted in applicable combatant command areas of responsibility.

2.4. DOT and DHS Responsibilities.

2.4.1. Information Dissemination. 

The DOT will provide NWS with timely dissemination of significant information received 

regarding tropical and subtropical cyclones.

2.4.2. Flight Assistance. 

Through the Federal Aviation Administration (FAA), the DOT will provide air traffic control, 

communications, and flight assistance services.

2.4.3. U. S. Coast Guard. 

The Department of Homeland Security (DHS) will provide the following through the U.S. Coast 

Guard:

• Personnel, vessel, and communications support to the NDBC for development, deployment, 

and operation of moored environmental data buoy systems.

• Surface observations to NWS from selected coastal facilities and vessels.

• Communications circuits for relay of weather observations to NWS in selected areas.

• Coastal broadcast facilities at selected locations for tropical storm or hurricane forecasts and 

warnings.

2.5. Annual Liaison with Other Nations.

2.5.1. The DOD, DOC, and DOT will cooperate in arranging an annual trip to the Caribbean 

and the Gulf of Mexico area to carry out a continuing and effective liaison with the directors of 

meteorological services, air traffic control agencies, and disaster preparedness agencies of 

nations in those areas, regarding the provision of tropical cyclone warning services. Due to the 

international importance of this mission, the Air Force Reserve Command (AFRC) and NHC 

will jointly plan and execute this mission annually. The NHC will coordinate with the 

meteorological services in the countries to be visited.

2.5.2. This annual liaison trip is known as the Caribbean Hurricane Awareness Tour (CHAT). It 

takes place in the United States Southern and Northern Command’s area of responsibility and 

supports their mission of promoting stability, collective security, and defending U.S. regional 

interests. The WC-130 aircraft flown by the 53rd Weather Reconnaissance Squadron (53rd WRS) 

“Hurricane Hunters” is the most visible symbol of this awareness program; it serves as an 

educational platform and as a media focus for both dignitaries and the local populace. Tours of 

the aircraft demonstrate the critical partnership between DOD and NOAA during the preparation 

of a tropical cyclone forecast. The CHAT increases public awareness of the hurricane threat and 

serves to recognize and strengthen national and international teamwork for storm warning and 

emergency response.

2.5.3. This diplomatic mission is unique in character and purpose. This joint AFRC and NOAA 

mission demonstrates the concerted U.S. effort to execute its hurricane program and illustrates 
2-5

the importance the U.S. places on hurricane forecasting, tracking, and warning. The CHAT helps 

communicate the U.S. responsibilities in the region and it highlights the vital roles of NOAA and 

53rd WRS. The media’s role is to document the trip and promote the hurricane preparedness 

message, thus providing visibility to this important outreach activity both nationally and 

internationally.

2.5.4. The synergy created by all participants traveling together on the 53rd WRS WC-130 

aircraft is essential to efficiently accomplishing the overall objectives of the mission while 

exercising fiscal responsibility. AFRC may support the mission on a non-interference basis for: 

U.S. Department of Commerce (DOC) and National Oceanic and Atmospheric Administration 

(NOAA) staff, and other U.S. officials as appropriate. Media support may be provided within 

appropriate public affairs guidelines. DOD, DOC and DOT will also cooperate on an annual trip 

as needed to domestic sites to accomplish similar objectives. This liaison trip is known as the 

Hurricane Awareness Tour (HAT). The HAT historically focuses on locations along the U.S. 

east and Gulf coasts (alternating annually) but can include international stops (e.g., Canada).

2.6. Air Traffic Control/Flight Operations Coordination. 

The operations officers of the principal flying units, the Manager, Air Traffic Control System 

Command Center (ATCSCC), Warrenton, VA, and the assistant managers for traffic 

management or assistant manager for military operations, as appropriate, at key Air Route 

Traffic Control Centers (ARTCC) will maintain a close working relationship on a continuing 

basis to ensure mission success under actual tropical storm conditions. This will involve visits to 

each other's facilities, familiarization flights, and telephone and electronic communications to 

improve the understanding of each other's requirements and capabilities.

2.6.1. Gulf of Mexico Weather Re connaissance. 

The 53rd Weather Reconnaissance Squadron and the NOAA Aircraft Operations Center 

operations officers will maintain a close working relationship with the ATCSCC, the ARTCCs, 

and the Fleet Aerial Control and Surveillance Facility (FACSFAC) for the coordination of 

weather reconnaissance flights in the Gulf of Mexico and over the Caribbean Sea in particular, 

and in the United States in general. The operations officers will:

• Request the assistance of the appropriate ARTCC/FACSFAC in support of the National 

Hurricane Operations Plan.

• Provide the current operations officer's name and telephone number to the appropriate 

ARTCC and FACSFAC.

• Publish the unit's telephone numbers [Defense Switched Network (DSN)/Commercial]).

2.6.2. Air Traffic Control Assistance. 

The ATCSCC, appropriate ARTCCs, and FACSFAC will maintain a close working relationship 

with the weather reconnaissance units and provide airspace and air traffic control assistance to 

the extent possible. Those organizations will:

• Provide the current names and telephone numbers of points of contact to the flying units.

• Publish telephone numbers (DSN/Commercial).
2-6 
3-1

CHAPTER 3: GENERAL OPERATIONS AND 

PROCEDURES OF THE NATIONAL WEATHER 

SERVICE HURRICANE CENTERS

3.1. General.

This chapter briefly describes the products, procedures, and communications headers used by the 

National Hurricane Center (NHC) and the Central Pacific Hurricane Center (CPHC). See 

Appendix A for a description of local National Weather Service (NWS) office products which 

support the tropical cyclone forecasting and warning program. Additional details of the products, 

including transmission times, can be found in National Weather Service Instruction 10-601, 

located at: http://www.nws.noaa.gov/directives/sym/pd01006001curr.pdf.

3.2. Products.

3.2.1. Tropical Weather Outlook (TWO).

NHC and CPHC prepare text and graphical versions of the TWO during their respective tropical 

cyclone seasons. The TWO covers tropical and subtropical waters and discusses areas of 

disturbed weather and the probability of tropical cyclone development. The NHC outlook, 

covering the next 120 hours, will mention tropical cyclones and subtropical cyclones, including 

the system's location (in either general terms or map coordinates), status, and change in status.

The CPHC outlook, covering the next 120 hours, will mention tropical cyclones, including the 

system’s location (in either general terms or map coordinates), status, and change in status.

3.2.2. Tropical Cyclone Public Advisories (TCP).

The TCP is the primary tropical cyclone information product issued to the public. The TCP 

comprises five sections: Summary, Watches and Warnings, Discussion and Outlook, Hazards, 

and Next Advisory. The NHC, the CPHC, and WFO Guam issue TCPs. The following pertains 

to the tropical storm/hurricane/typhoon watches and warnings contained in the TCP:

• NHC. NHC issues tropical storm/hurricane watches/warnings for the Atlantic, Pacific, and 

Gulf of Mexico coasts of the continental United States, the US Virgin Islands, and Puerto 

Rico. NHC issues watches when conditions along the coast are possible within 48 hours.

NHC issues warnings when conditions along the coast are expected within 36 hours.

[NOTE: Because hurricane preparedness activities become difficult once winds reach 

tropical storm force, NHC issues the hurricane/typhoon watches 48 hours in advance of the 

anticipated onset of tropical-storm-force winds.]

• CPHC and WFO Guam. CPHC and WFO Guam issues tropical storm/hurricane/typhoon 

watches/warnings for the islands of Hawaii, northwest Hawaiian Islands, Johnston Atoll, 

Guam, Northern Mariana Islands and selected points in the Micronesian countries. CPHC 

and WFO Guam issue watches when conditions along the coast are possible within 48 hours.

CPHC and WFO Guam issue warnings when conditions are expected along the coast within 

36 and 24 hours, respectively.
3-2

[NOTE: Because hurricane/typhoon preparedness activities become difficult once winds 

reach tropical storm force, CPHC and WFO Guam issue the hurricane/typhoon watches 48 

hours in advance of the anticipated onset of tropical-storm-force winds.]

Intermediate public advisories will be issued in-between scheduled or special advisories when 

watches or warnings are in effect. They will continue to be issued when a tropical storm or 

hurricane is inland, even after coastal watches/warnings have been discontinued. These will 

retain the number of the last advisory they update plus an alphabetic designator (e.g., 

HURRICANE ALLISON INTERMEDIATE ADVISORY NUMBER 20A).

3.2.3. Tropical Cyclone Forecast/Advisories (TCM).

NHC and CPHC will prepare TCMs for all tropical cyclones within their area of responsibility.

See Section 4.3 for content and format of the advisories. The TCM provides critical tropical 

cyclone watch, warning, and forecast information for the protection of life and property.

[Note: In the Western Pacific, tropical cyclone forecasts/advisories are issued by the 

JTWC. Appendix C provides a listing of the abbreviated communications headings and 

titles for JTWC products. Information on the broadcast of tropical cyclone information to 

coastal and high-seas shipping can be found in Chapter 10, Marine Weather Broadcasts.]

3.2.4. Tropical Cyclone Discussions (TCD).

The TCD is a primary tropical cyclone product explaining forecaster’s reasoning behind analysis 

and the forecast for a tropical cyclone. It also provides coordinated 12-, 24-, 36-, 48-, 72-, 96-, 

and 120-hour tropical cyclone forecast positions and maximum sustained wind speed forecasts; 

other meteorological decisions; and plans for watches and warnings.

3.2.5. Tropical Cyclone Updates (TCU).

TCUs are issued to inform users of significant changes in a tropical cyclone in-between regularly 

scheduled public advisories. Such uses include, but are not limited to the following: to provide 

timely information of an unusual nature, such as the time and location of landfall, or to announce 

an expected change in intensity that results in an upgrade or downgrade of status (e.g., from a 

tropical storm to a hurricane); to provide a continuous flow of information regarding the center 

location of a tropical cyclone when watches or warnings are in effect and the center can be easily 

tracked with land-based radar; to provide advance notice that significant changes to storm 

information will be conveyed shortly, either through a subsequent TCU or through a Special 

Advisory; to announce changes to international watches or warnings made by other countries, or 

to cancel U.S. watches or warnings; or to issue a U.S. watch or warning, but only if the TCU 

precedes a special advisory that will contain the same watch/warning information, and indicates 

the special advisory will be issued shortly.

The TCU is a brief alphanumeric text product containing either block paragraph text, or a 

formatted storm summary section, or both. The storm summary section is identical in format to 

the storm summary section found in the TCP. The storm summary section is required whenever 

the TCU is issued to update storm intensity, location, or motion information. The storm summary 

section is not required for TCUs issued to provide advance notice that significant changes to 

storm information will be conveyed shortly, or for those issued to convey changes to watches or 

warnings. TCUs issued to provide hourly storm location information will contain a headline 

indicating the purpose of the TCU (e.g., “...11 AM POSITION UPDATE...”).
3-3

3.2.6. Graphical Tropical Cyclone Surface Wind Speed Probabilities.

This graphical product portrays probabilistic surface wind speed information which will help 

users prepare for the potential of tropical storm or hurricane conditions. This product shows 

probabilities for three wind speed thresholds: 34, 50 and 64 knots. It provides cumulative 

probabilities through each 12 hour interval (e.g. 0 -12 hours, 0- 24 hours, etc.) from 0 through 

120 hours. They are available in graphical forms in a static and an animated display. These wind 

speed probabilities are based on the track, intensity, and wind structure uncertainties in the 

official forecasts from the tropical cyclone centers.

3.2.7. Tropical Cyclone Surface Wind Speed Probabilities Text Product (PWS).

This product portrays probabilistic wind speed information helping users prepare for the 

potential of tropical storm or hurricane conditions.

The probabilities in this product are statistically based on the errors in the official track and 

intensity forecasts issued during the past five years by NHC and CPHC. Variability in tropical 

cyclone wind structure is also incorporated. New probability values are computed for each new 

official forecast issued by NHC or CPHC.

Probabilities for specific locations are provided for sustained wind speeds equal to or exceeding 

three wind speed thresholds: 34, 50 and 64 knots. Two types of probability values are provided 

in this table: onset and cumulative. Onset probabilities are provided for each of the following 

time intervals: 0-12 hours, 12-24 hours, 24-36 hours, 36-48 hours, 48-72 hours, 72-96 hours, and 

96-120 hours. These individual period probabilities indicate the chance that the particular wind 

speed will start during each individual period at each location. Cumulative probabilities are 

produced for the following time periods: 0-12 hours, 0-24 hours, 0-36 hours, 0-48 hours, 0-72 

hours, 0-96 hours, and 0-120 hours. These cumulative probabilities indicate the overall chance 

the particular wind speed will occur at each location during the period between hour 0 and the 

forecast hour.

3.2.8. Tropical Cyclone Watch Warning Product (TCV). 

The national TCV is based upon the Valid Time Event Code (VTEC). It summarizes all new, 

continued, and cancelled tropical cyclone watches and warnings issued by the NHC for the U.S. 

Atlantic and Gulf coast, southern California coast, Puerto Rico, and U.S. Virgin Islands. In the 

Atlantic, the NHC-issued TCV also contains the inland VTEC provided by NWS Weather 

Forecast Offices (WFOs). The CPHC will issue a TCV for the main islands of the State of 

Hawaii. The product is issued each time a U. S. tropical cyclone watch and/or warning is issued, 

continued, or discontinued for all Atlantic, portions of the North East Pacific, and the North 

Central Pacific Ocean basin tropical cyclones.

The local TCV text is a segmented, nearly automated, VTEC product with each segment being a 

discrete forecast zone. It is issued by coastal Weather Forecast Offices (WFOs) in the Atlantic 

and North Central Pacific basins. Each segment contains land-based tropical cyclone 

watches/warnings in effect, meteorological information, threats (Wind, Storm Surge, Flooding 

Rain, Tornadoes) and their potential impacts. The product is generated from local gridded 

information and national guidance and is, therefore, not intended to be manually edited by the 

forecaster. This text product is intended for parsing by the weather enterprise, and is paired with 

the WFO Hurricane Local Statement (HLS) to provide a complete, localized tropical forecast. It 
3-4

can also be useful to decision makers as it provides detailed information on timing, threats, and 

impacts on a zone level.

3.2.9. Weather Prediction Center (WPC) Public Advisories (TCP).

The National Centers for Environmental Prediction’s WPC issues public advisories after NHC 

discontinues its advisories on subtropical and tropical cyclones that have moved inland in the 

conterminous United States or Mexico, but still pose a threat of heavy rain and flash floods in the 

conterminous United States or Mexico. The last NHC advisory will normally be issued when 

winds in an inland tropical cyclone drop below tropical storm strength, and the tropical 

depression is not forecast to regain tropical storm intensity or re-emerge over water. Therefore 

WPC will only handle tropical depressions or remnants. WPC advisories will terminate when the 

threat of flash flooding has ended.

3.2.10. Other Tropical Cyclone Products.

Several other tropical cyclone related products are issued to support the tropical cyclone 

forecasting and warning program. Refer to NWS Instruction 10-601, located at 

http://www.nws.noaa.gov/directives/sym/pd01006001curr.pdf, for further details on these 

products, which include:

• Satellite Interpretation Message (SIM).

• Tropical Weather Discussion (TWD).

• Tropical Weather Summary (TWS).

• Tropical Cyclone Summary – Fixes (TCS).

• Tropical Cyclone Danger Area Graphic

• Aviation Tropical Cyclone Advisory (TCA)

• Tropical Cyclone Reports (TCR)

• Tropical Cyclone Track and Watch/Warning Graphic

• Cumulative Wind Distribution

• Tropical Cyclone Surface Wind Field Graphic

• Maximum Wind Speed Probability Table

• Tropical Cyclone Storm Surge Probabilities

3.2.11. NHC and CPHC Continuance of Advisories and Products for Post-Tropical 

Cyclones. 

The NHC and CPHC will continue issuing advisory products after a tropical cyclone becomes 

post-tropical in those cases where the system continues to pose a significant threat to life and 

property and where the transfer or responsibility to another office would result in an 

unacceptable discontinuity of service. Similarly, WFO Guam will continue issuing advisory 

products after a tropical cyclone becomes post-tropical in those cases where the system continues 

to pose a significant threat to life and property.

3.3. Numbering and Naming of Tropical and Subtropical Cyclones. 

The hurricane centers will number tropical depressions in their areas of responsibility. 

Depression numbers are always spelled out (e.g., "ONE,” "TWO," "THREE," etc.). Depression 

numbers are assigned to match the seasonal cyclone number, even if a previous cyclone has 

bypassed the depression stage. For example, if the first tropical cyclone of the season forms 
3-5

directly as a storm (e.g., a fast-moving tropical wave becomes a tropical storm without ever 

becoming a depression), then the depression number "ONE" would simply be skipped and not 

used until the following year. For ease in differentiation, tropical depression numbers shall 

include the suffix "E" for Eastern Pacific, "C" for Central Pacific, or "W" for Western Pacific, 

after the number.

In both the Atlantic and Pacific, once the depression has reached tropical storm intensity, it shall 

be named and the depression number dropped. The depression number will not be used again 

until the following year. Give tropical cyclones a name in the first advisory after intensifying to 

34 knots (39 mph) or greater. In the Western Pacific, WFO Guam will use the JTWC cyclone 

number for all non-named systems. For RSMC Tokyo named systems, WFO Guam will use the 

RSMC Tokyo name with the associated JTWC number in parentheses.

The following rules apply for tropical cyclones passing from one basin to another: Retain the 

name if a tropical cyclone passes from one basin into another basin as a tropical cyclone; i.e., 

advisories are continuous. An unnamed tropical depression will also retain its number (e.g. 

Tropical Depression Six-E remains Tropical Depression Six-E) if it crosses into another area of 

responsibility. For unnamed tropical depressions moving from west to east across 180°, CPHC 

will use the associated Joint Typhoon Warning Center’s (JTWC) number and indicate JTWC in 

parentheses following the number. For named systems, CPHC will use the associated RSMC 

Tokyo name and provide the associated JTWC number in parentheses.

Within a basin, if the remnant of a tropical cyclone redevelops into a tropical cyclone, it is 

assigned its original number or name. If the remnants of a former tropical cyclone regenerate in a 

new basin, the regenerated tropical cyclone will be given a new designation. 

3.3.1. Atlantic Basin.

Depression numbers, ONE, TWO, THREE, will be assigned by the NHC after advising the Fleet 

Weather Center, Norfolk. Annual lists of Atlantic storm names are provided in Table 3-2.

3.3.2. Pacific East of 140°W.

Depression numbers, with the suffix E, e.g., ONE-E, TWO-E, THREE-E, will be assigned by the 

NHC after advising JTWC, Pearl Harbor, HI. The assigned identifier shall be retained even if the 

depression passes into another warning area. Annual lists of Eastern Pacific storm names are 

provided in Table 3-3.

3.3.3. Pacific West of 140°W and East of 180°.

Depression numbers, with suffix C; e.g., ONE-C, TWO-C, THREE-C, will be assigned by the 

CPHC after advising JTWC. Rotating lists of Central Pacific storm names are provided in Table 

3-4.

3.3.4. Pacific West of 180° and North of 0°.

Depression numbers, with suffix W; e.g., ONE-W, TWO-W, THREE-W, are assigned by JTWC. 

Rotating lists of Western Pacific storm names are provided in Table 3-5.

3.3.5. Subtropical Depressions.
3-6

A single list of numbers and names will be used for all tropical and subtropical cyclones in each 

basin. Therefore, numbering of subtropical depressions will follow the same procedure as 

tropical depressions. For example, if the first subtropical depression follows the first tropical 

depression, the subtropical depression will be given the designation SUBTROPICAL 

DEPRESSION TWO. If a subtropical depression becomes a subtropical storm, it receives the 

next available name in the tropical cyclone naming sequence.

3.4. Transfer of Warning Responsibility.

3.4.1. NHC to CPHC.

When a tropical or subtropical cyclone approaches 140°W, the coordinated transfer of warning 

responsibility from NHC to CPHC will be made and the appropriate advisory issued.

3.4.2. CPHC to JTWC/(RSMC, Tokyo)/WFO Guam.

When a tropical or subtropical cyclone crosses 180° from east to west, the coordinated transfer of 

warning responsibility from CPHC to JTWC will be made and the appropriate advisory issued.

At the same time, the CPHC will coordinate with the RSMC, Tokyo and WFO Guam so that 

they are aware that CPHC will be suspending the issuance of advisories.

3.4.3. JTWC/RSMC, Tokyo to CPHC.

When a tropical or subtropical cyclone crosses 180° from west to east, the coordinated transfer of 

warning responsibility from JTWC to CPHC will be made. At the same time, the CPHC will 

coordinate with RSMC, Tokyo so that they are aware that CPHC will be assuming the issuance 

of advisories.

3.5. Alternate Warning Responsibilities.

3.5.1. Transfer to Alternate.

In the event of impending or actual operational failure of a hurricane forecast center, tropical 

warning responsibilities will be transferred to an alternate facility in accordance with existing 

directives and retained there until resumption of responsibility can be made. Alternate facilities 

are listed in Table 1.
3-7

Table 3-1. Primary and alternate operational warning responsibilities.

PRIMARY ALTERNATE

NHC

Atlantic Basin: National Centers for 

Environmental Prediction Weather Prediction 

Center (WPC), College Park, MD

Eastern Pacific Basin: CPHC

CPHC NHC

CARCAH 53rd Weather Reconnaissance Squadron (53 

WRS)

JTWC

Fleet Numerical Meteorology and 

Oceanography Center (FLENUMETOCCEN), 

Monterey, CA

WFO Guam CPHC

3.5.2. Notification.

The Fleet Weather Center, Norfolk, and JTWC, Pearl Harbor, will be advised by NHC, 

CARCAH, and CPHC, as appropriate, of impending or actual transfer of responsibility by the 

most rapid means available. JTWC will advise CPHC, NHC, and WFO Guam of impending or 

actual transfer of JTWC responsibilities. In the event of a CARCAH operational failure, direct 

communication is authorized between the 53 WRS and the forecast facility. Contact 53 WRS at 

DSN 597-2409/228-377-2409 or through the Keesler AFB Command Post at DSN 597-

4181/4330; COM 228-377-4181/4330 (ask for the 53 WRS).
3-8

Table 3-2. Atlantic Tropical Cyclone Names

[Note: If over 21 tropical cyclones occur in a year, the Greek alphabet will be used 

following the W-named cyclone.]

2019

Name Pronunciation

Andrea AN-dree-uh

Barry BAIR-ree

Chantal shahn-TAHL

Dorian DOR-ee-an

Erin AIR-rin

Fernand fair-NAHN

Gabrielle ga-bree-ELL

Humberto oom-BAIR-toh

Imelda ee-MEHL-dah

Jerry JEHR-ee

Karen KAIR-ren

Lorenzo loh-REN-zoh

Melissa meh-LIH-suh

Nestor NES-tor

Olga OAL-guh

Pablo PAHB-lo

Rebekah reh-BEH-kuh

Sebastien suh-BASH-chuhn

Tanya TAHN-yuh

Van van

Wendy WEN-dee

2018

Name Pronunciation

Alberto al-BAIR-toe

Beryl BEHR-ril

Chris kris

Debby DEH-bee

Ernesto er-NES-toh

Florence FLOOR-ence

Gordon GOR-duhn

Helene heh-LEEN

Isaac EYE-zik

Joyce joyss

Kirk kurk

Leslie LEHZ-lee

Michael MY-kuhl

Nadine nay-DEEN

Oscar AHS-kur

Patty PAT-ee

Rafael rah-fah-ELL

Sara SAIR-uh

Tony TOH-nee

Valerie VAH-lur-ee

William WILL-yum

2017

Name Pronunciation

Arlene ar-LEEN

Bret bret

Cindy SIN-dee

Don dahn

Emily EH-mih-lee

Franklin FRANK-lin

Gert gert

Harvey HAR-vee

Irma ER-mah

Jose ho-ZAY

Katia KAH-tyah

Lee lee

Maria ma-REE-ah

Nate nait

Ophelia o-FEEL-ya

Philippe fee-LEEP

Rina REE-nuh

Sean shawn

Tammy TAM-ee

Vince vinss

Whitney WHIT-nee

2020

Name Pronunciation

Arthur AR-thur

Bertha BUR-thuh

Cristobal krees-TOH-bahl

Dolly DAH-lee

Edouard eh-DWARD

Fay fay

Gonzalo gohn- SAH-loh

Hanna HAN-uh

Isaias ees-ah-EE-ahs

Josephine JOH-seh-feen

Kyle KY-ull

Laura LOOR-ruh

Marco MAR-koe

Nana NA-na

Omar OH-mar

Paulette pawl-LET

Rene re-NAY

Sally SAL-ee

Teddy TEHD-ee

Vicky VIH-kee

Wilfred WILL-fred

2021

Name Pronunciation

Ana AH-nah

Bill bill

Claudette klaw-DET

Danny DAN-ee

Elsa EL-suh

Fred frehd

Grace grayss

Henri ahn-REE

Ida EYE-duh

Julian JOO-lee-uhn

Kate kayt

Larry LAIR-ree

Mindy MIN-dee

Nicholas NIH-kuh-luss

Odette oh-DEHT

Peter PEE-tur

Rose rohz

Sam sam

Teresa tuh-REE-suh

Victor VIK-tur

Wanda WAHN-duh

2022

Name Pronunciation

Alex AL-leks

Bonnie BAH-nee

Colin KAH-lihn

Danielle dan-YELL

Earl URR-ull

Fiona fee-OH-nuh

Gaston ga-STAWN

Hermine her-MEEN

Ian EE-an

Julia JOO-lee-uh

Karl KAR-ull

Lisa LEE-suh

Martin MAR-tin

Nicole nih-KOHL

Owen OH-uhn

Paula PAHL-luh

Richard RIH-churd

Shary SHAHR-ee

Tobias toh-BEE-uss

Virginie vir-JIN-ee

Walter WALL-tur
3-9

Table 3-3. Eastern Pacific Tropical Cyclone Names

2019

Name Pronunciation

Alvin AL-vin

Barbara BAR-bruh

Cosme COS-may

Dalila dah-LY-lah

Erick EHR-ik

Flossie FLOSS-ee

Gil gill

Henriette hen-ree-ETT

Ivo eye-VOH

Juliette jew-lee-EHT

Kiko KEE-ko

Lorena low-RAY-na

Mario MAR-ee-o

Narda NAHR-duh

Octave AHK-tayv

Priscilla prih-SIH-luh

Raymond RAY-mund

Sonia SOHN-yah

Tico TEE-koh

Velma VELL-muh

Wallis WAHL-lis

Xina ZEE-nah

York york

Zelda ZEL-dah

2018

Name Pronunciation

Aletta a-LET-ah

Bud buhd

Carlotta kar-LOT-uh

Daniel DAN-yuhl

Emilia ee-MILL-ya

Fabio FAH-bee-o

Gilma GIL-mah

Hector HEHK-tor

Ileana ill-ay-AH-nah

John jahn

Kristy KRIS-tee

Lane layne

Miriam MEER-yim

Norman NOR-muhn

Olivia uh-LIV-ee-uh

Paul pall

Rosa ROH-zuh

Sergio SIR-gee-oh

Tara TAIR-uh

Vicente vee-CEN-tay

Willa WIH-lah

Xavier ZAY-vee-ur

Yolanda yo-LAHN-da

Zeke zeek

2017

Name Pronunciation

Adrian AY-dree-uhn

Beatriz BEE-a-triz

Calvin KAL-vin

Dora DOR-ruh

Eugene YOU-jeen

Fernanda fer-NAN-dah

Greg greg

Hilary HIH-luh-ree

Irwin UR-win

Jova HO-vah

Kenneth KEH-neth

Lidia LIH-dyah

Max maks

Norma NOOR-muh

Otis OH-tis

Pilar Pee-LAHR

Ramon rah-MOHN

Selma SELL-mah

Todd tahd

Veronica vur-RAHN-ih-kuh

Wiley WY-lee

Xina ZEE-nah

York york 

Zelda ZEL-dah

2020

Name Pronunciation

Amanda uh-MAN-duh

Boris bor-EES

Cristina kris-TEE-nuh

Douglas DUG-luss

Elida ELL-ee-dah

Fausto FOW-sto

Genevieve jeh-nuh-VEEV

Hernan her-NAHN

Iselle ee-SELL

Julio HOO-lee-o

Karina kuh-REE-nuh

Lowell LO-uhl

Marie muh-REE

Norbert NOR-bert

Odalys oh-DAL-ess

Polo POH-loh

Rachel RAY-chull

Simon SY-muhn

Trudy TROO-dee

Vance vanss

Winnie WIN-ee

Xavier ZAY-vee-ur

Yolanda yo-LAHN-da

Zeke zeek

2021

Name Pronunciation

Andres ahn-DRASE

Blanca BLAHN-kah

Carlos KAR-loess

Dolores deh-LOOR-ess

Enrique ahn-REE-kay

Felicia fa-LEE-sha

Guillermo gee-YER-mo

Hilda HILL-duh

Ignacio eeg-NAH-see-oh

Jimena he-MAY-na

Kevin KEH-vin

Linda LIHN-duh

Marty MAR-tee

Nora NOOR-ruh

Olaf OH-lahf

Pamela PAM-eh-luh

Rick rik

Sandra SAN-druh

Terry TAIR-ree

Vivian VIH-vee-uhn

Waldo WAHL-doh

Xina ZEE-nah

York york

Zelda ZEL-dah

2022

Name Pronunciation

Agatha A-guh-thuh

Blas blahs

Celia SEEL-yuh

Darby DAR-bee

Estelle eh-STELL

Frank frank

Georgette jor-JET

Howard HOW-urd

Ivette ee-VET

Javier hahv-YAIR

Kay kay

Lester LESS-tur

Madeline MAD-eh-luhn

Newton NOO-tuhn

Orlene or-LEEN

Paine payne

Roslyn RAWZ-luhn

Seymour SEE-mor

Tina TEE-nuh

Virgil VUR-jill

Winifred WIN-ih-fred

Xavier ZAY-vee-ur

Yolanda yo-LAHN-da

Zeke zeek
3-10

Table 3-4. Central Pacific Tropical Cyclone Names

COLUMN 1 COLUMN 2

Name Pronunciation Name Pronunciation

AKONI ah-KOH-nee AKA AH-kah

EMA EH-mah EKEKA eh-KEH-kak

HONE HOH-neh HENE HEH-neh

IONA ee-OH-nah IOLANA ee-OH-lah-nah

KELI KEH-lee KEONI keh-ON-nee

LALA LAH-lah LINO LEE-noh

MOKE MOH-keh MELE MEH-leh

NOLO NOH-loh NONA NOH-nah

OLANA Oh-LAH-nah OLIWA oh-LEE-vah

PENA PEH-nah PAMA PAH-mah

ULANA oo-LAH-nah UPANA oo-PAH-nah

WALE WAH-leh WENE WEH-neh

COLUMN 3 COLUMN 4

Name Pronunciation Name Pronunciation

ALIKA ah-LEE-kah ANA AH-nah

ELE EH-leh ELA EH-lah

HUKO HOO-koh HALOLA hah-LOH-lah

IOPA ee-OH-pah IUNE ee-OO-neh

KIKA KEE-kah KILO KEE-lo

LANA LAH-nah LOKE LOH-keh

MAKA MAH-kah MALIA mah-LEE-ah

NEKI NEH-kee NIALA nee-AH-lah

OMEKA oh-MEH-kah OHO OH-hoh

PEWA PEH-vah PALI PAH-lee

UNALA oo-NAH-lah ULIKA oo-LEE-kah

WALI WAH-lee WALAKA wah-LAH-kah

[Note: Use Column 1 list of names until exhausted before going to Column 2, etc. All letters 

in the Hawaiian language are pronounced, including double or triple vowels.]
3-11

Table 3-5. International Tropical Cyclone Names for the Northwest Pacific and South 

China Sea

Contributor I II III IV V

NAME NAME NAME NAME NAME

Cambodia Damrey Kong-rey Nakri Krovanh Sarika

China Longwang Yutu Fengshen Dujuan Haima

DPR Korea Kirogi Toraji Kalmaegi Maemi Meari

HK, China Kai-tak Man-yi Fung-wong Choi-wan Ma-on

Japan Tembin Usagi Kammuri Koppu Tokage

Lao PDR Bolaven Pabuk Phanfone Ketsana Nock-ten

Macau Chanchu Wutip Vongfong Parma Muifa

Malaysia Jelawat Sepat Nuri Melor Merbok

Micronesia Ewiniar Fitow Sinlaku Nepartak Nanmadol

Philippines Bilis Danas Hagupit Lupit Talas

RO Korea Kaemi Nari Changmi Sudal Noru

Thailand Prapiroon Wipha Mekkhala Nida Kulap

U.S.A. Maria Francisco Higos Omais Roke

Viet Nam Saomai Lekima Bavi Conson Sonca

Cambodia Bopha Krosa Maysak Chanthu Nesat

China Wukong Haiyan Haishen Dianmu Haitang

DPR Korea Sonamu Podul Pongsona Mindulle Nalgae

HK, China Shanshan Lingling Yanyan Tingting Banyan

Japan Yagi Kajiki Kujira Kompasu Washi

Lao PDR Xangsane Faxai Chan-hom Namtheun Matsa

Macau Bebinca Peipan Linfa Malou Sanvu

Malaysia Rumbia Tapah Nangka Meranti Mawar

Micronesia Soulik Mitag Soudelor Rananim Guchol

Philippines Cimaron Hagibis Molave Malakas Talim

RO Korea Chebi Noguri Koni Megi Nabi

Thailand Durian Rammasun Morakot Chaba Khanun

U.S.A. Utor Matmo Etau Aere Vicente

Viet Nam Trami Halong Vamco Songda Saola

[NOTE: The official international name list was effective January 1, 2000. Names will be 

assigned in rotation starting with Damrey for the first tropical cyclone of the year 2000 

which is of tropical storm strength or greater. When the last name in column 5 (Saola) is 

used, the sequence will begin again with the first name in column 1.]

3.6. Abbreviated Communications Headings.

Abbreviated communications headings are assigned to advisories on tropical and subtropical 

cyclones and other advisories based on depression numbers or storm name and standard 
3-12

communications procedures governed by the World Meteorological Organization (WMO). An 

abbreviated heading consists of three groups with ONE space between each of the groups. The 

first group contains a data type indicator (e.g., WT for hurricane), a geographical indicator (e.g. 

NT for Atlantic Basin), and a number. The second group contains a location identifier of the 

message originator (e.g., KNHC for NHC). The third group is a date-time group in UTC. An 

example of a complete header is: WTNT61 KNHC 180400. Table 3-6 provides the abbreviated 

communications headings for products issued by NHC, CPHC, and WFO Guam.

Table 3-6. Summary of Products and their Associated WMO Header

PRODUCT TITLE WMO HEADER

Tropical Weather Outlook

Atlantic Basin ABNT20 KNHC

Eastern Pacific ABPZ20 KNHC

Central Pacific ACPN50 PHFO

Tropical Weather Discussion

Atlantic Basin AXNT20 KNHC

Eastern Pacific AXPZ20 KNHC

Tropical/Subtropical Cyclone Public Advisory

Atlantic Basin WTNT31-35 KNHC

Eastern Pacific WTPZ31-35 KNHC

Central Pacific WTPA31-35 PHFO

Western Pacific WTPQ31-35 PGUM

Tropical Cyclone Surface Wind Speed Probabilities Text Product

Atlantic Basin FONT11-15 KNHC

Eastern Pacific FOPZ11-15 KNHC

Central Pacific FOPA11-15 PHFO

Tropical/Subtropical Cyclone Forecast/Advisory

Atlantic Basin WTNT21-25 KNHC

Eastern Pacific WTPZ21-25 KNHC

Central Pacific WTPA21-25 PHFO

Tropical Cyclone Discussion

Atlantic Basin WTNT41-45 KNHC

Eastern Pacific WTPZ41-45 KNHC

Central Pacific WTPA41-45 PHFO

Tropical Cyclone Valid Time Event Code Product

Atlantic Basin WTNT81-85 KNHC

Eastern Pacific WTPZ81-85 KNHC

Central Pacific WTPA81-85 PHFO

Tropical Cyclone Update

Atlantic Basin WTNT61-65 KNHC

Eastern Pacific WTPZ61-65 KNHC

Central Pacific WTPA61-65 PHFO

Tropical Weather Summary

Atlantic Basin ABNT30 KNHC

Eastern Pacific ABPZ30 KNHC

Central Pacific ACPN60 PHFO
3-13

Table 3-6 (continued). Summary of Products and their Associated WMO Header

PRODUCT TITLE WMO HEADER

Tropical Cyclone Position and Intensity from Satellite Data

South Central Pacific 120W TXPS40 PHFO

North Central Pacific 140W - 180 TXPN40 PHFO

Satellite Interpretation Message

West Pacific (Guam) ATPQ40 PGUM

Satellite-Derived Rainfall

Eastern Caribbean TCCA21 KNHC

Central Caribbean TCCA22 KNHC

Western Caribbean TCCA23 KNHC

Aviation Tropical Cyclone Advisory Message

Atlantic Basin FKNT21-25 KNHC

Eastern Pacific FKPZ21-25 KNHC

Central Pacific FKPA21-25 PHFO

Tropical Cyclone Summary - Fixes

South Central Pacific 120W TXPS41-45 PHFO

North Central Pacific 140W - 180 TXPN41-45 PHFO

[Note: Refer to Appendix C for abbreviated communications headers and titles for the 

products for which JTWC is responsible.]

3.7.Hurricane Liaison Team (HLT). 

The HLT is a Department of Homeland Security’s Federal Emergency Management Agency 

(FEMA)-sponsored team made up of federal, state, and local emergency managers who have 

extensive hurricane operational experience. Team members function as a bridge between 

scientists, meteorologists and the emergency managers who respond if the storm threatens the 

United States or its territories. Team members provide immediate and critical storm information 

to government agency decision makers at all levels to help them prepare for their response 

operations, which may include evacuations, sheltering, and mobilizing equipment. State and/or 

local officials, not the HLT, make decisions concerning evacuations.

3.7.1. National Weather Service (NWS) Responsibilities.

The NWS supports the HLT through use of NHC meteorologists, Weather Forecast Office 

(WFO) personnel (typically warning coordination meteorologists and service hydrologists), and 

River Forecast Center (RFC) hydrologists. Eastern and Southern Region Headquarters will 

maintain a list of their available HLT candidates.

3.7.2. Activation/Deployment.
3-14

On June 1st, or earlier if necessary, the NHC Director will request that the FEMA activate the 

HLT by contacting the Disaster Operations Directorate. The HLT will remain active throughout 

the season. When a tropical cyclone in the Atlantic or eastern North Pacific basins threatens the 

United States or its territories, the Director or Deputy Director of NHC may request NWS 

meteorological and/or hydrological support by contacting the appropriate NWS Regional 

Director. NWS personnel should deploy to NHC within 24 hours of the request for assistance.

NWS personnel will remain deployed at the HLT until the hurricane threat has passed. However, 

if a significant rainfall threat is expected to persist after landfall, the HLT will remain staffed by 

the FEMA to facilitate coordination with the Weather Prediction Center (WPC), who will 

assume briefing responsibilities until the rainfall threat has passed. NHC and WPC will 

coordinate the transfer of briefing responsibilities. During the inland event the HLT and WPC

will coordinate with the appropriate WFOs and RFCs, and when needed, hydrologists from the 

RFCs will provide hydrological briefings. 

If the HLT is deactivated, the WPC will assume the briefing duties provided the remnants of the 

tropical cyclone remain a threat to inland areas. NHC and WPC will coordinate prior to the 

transfer. During the inland event WPC will coordinate with the appropriate WFOs and RFCs and 

when needed, hydrologists from the RFCs will provide hydrological briefings.

3.7.3. Training.

Completing NWS/FEMA’s distance learning training module, Community Hurricane 

Preparedness, is required by HLT members. The module can be taken via the Internet at: 

http://meted.ucar.edu/hurrican/chp/index.htm. Other training opportunities are strongly 

encouraged. They are: FEMA’s “Introduction to Hurricane Preparedness” conducted at NHC for 

emergency mangers and NWS personnel, and FEMA’s annual HLT training session held at 

NHC.

3.7.4. Meteorological Duties.

The HLT meteorologist will:

• Establish and maintain contact with the impacted WFOs, RFCs, and the WPC. 

• Facilitate participation of the impacted NWS offices in conference calls, briefings, and in 

preparation and distribution of graphics.

• Provide meteorological interpretations on NHC advisories, WFO hurricane local statements, 

Hurrevac products, and storm surge forecasts for Federal, state and local agencies on request.

• Provide storm briefings via video/audio teleconferences for Federal, state and local 

organizations.

• Respond to meteorology-related incoming calls from Federal, state, and local emergency 

managers. Refer callers to the appropriate WFO for responses to localized special questions 

and issues. 

3.7.5. Hydrologic Duties.

The HLT hydrologist will:

• Establish and maintain contact with the impacted local WFOs, RFCs, and the WPC.

• Facilitate participation of the impacted NWS offices in conference calls, briefings, and in 

preparation and distribution of graphics. 
3-15

• Provide hydrologic interpretation on NHC advisories, WFO hurricane local statements, and 

WFO and RFC hydrologic products for Federal, state and local agencies on request. 

• Provide technical support for RFC lead during hydrologic portion of video teleconference. In 

absence of the RFC, lead the hydrologic portion of the video teleconference. 

• Respond to hydrology-related incoming calls from Federal, state, and local emergency 

managers. Refer callers to the appropriate WFO for responses to localized special questions 

and issues.
3-16
4-1

CHAPTER 4: NATIONAL WEATHER SERVICE 

PRODUCTS FOR THE DEPARTMENT OF DEFENSE

4.1. General.

The Department of Defense (DOD) and the Department of Commerce (DOC) weather forecasting, 

reconnaissance, and distribution agencies share technical information and some responsibilities. 

Mutually supportive relationships have developed over the years and have resulted in a mutual 

dependency. Due to the nature and distribution of DOD resources and operations, the DOD 

requires certain meteorological information beyond that available to the general public. 

Accordingly, the DOC provides DOD with special observations and advisories on tropical and 

subtropical storms threatening DOD resources or operations.

4.2. Observations.

The National Hurricane Center (NHC) and Central Pacific Hurricane Center (CPHC) will make 

available to DOD all significant tropical and subtropical cyclone observations that they receive.

4.3. Tropical Cyclone Forecast/Advisories.

4.3.1. General.

The NHC and CPHC will provide to DOD forecasts and related information for tropical and 

subtropical weather disturbances of depression intensity or greater. Forecasts will include location, 

movement, intensity, and dimension of the disturbances. Tropical cyclone forecast/advisories will 

be disseminated through the National Weather Service (NWS) communications facility at 

Suitland, MD, to the Weather Product Management and Distribution System (WPMDS) at the Air 

Force’s 557th Weather Wing (557 WW), Offutt AFB, NE, for further relay to DOD agencies. The 

DOD forecasters, who must give advice concerning an imminent operational decision, may 

contact the appropriate hurricane center forecaster (see Chapter 2) when published tropical 

cyclone forecast/advisories require elaboration. Telephone numbers for the hurricane centers are 

in Appendix I.

4.3.2. Tropical Cyclone Forecast/Advisory Issue Frequency. 

The first tropical cyclone forecast/advisory will normally be issued when meteorological data 

indicate that a tropical or subtropical cyclone has formed. Subsequent advisories will be issued at 

0300, 0900, 1500, and 2100 UTC from NHC and CPHC. The public advisories issued by the NWS 

Forecast Office (WFO) Guam, are issued 1 hour after the JTWC guidance. Advisories will 

continue to be issued until the system is classified below the depression intensity level. In addition, 

special forecasts will be issued whenever the following criteria are met:

• A significant change has occurred, requiring the issuance of a revised forecast package.

• Conditions require a hurricane or tropical storm watch or warning to be issued. Remarks 

stating the reason for the special forecast or the relocation will be mandatory in all special 

forecasts or advisories that include a relocated position.
4-2

4.3.3. Tropical Cyclone Forecast/Advisory Content. 

Tropical cyclone forecast/ advisories issued by the NHC and CPHC will contain appropriate 

information as shown in Figure 4-1. The forecast will contain 12, 24, 36, 48, 72, 96, and 120-hour 

tropical cyclone forecast positions. A code string is appended at the end of the line "NWS 

NATIONAL HURRICANE CENTER MIAMI FL." This is the Automated Tropical Cyclone 

Forecasting (ATCF) System Storm Identification Character String recognized by the WMO for 

tracking and verification of tropical cyclones. The ATCF <Storm ID> is three spaces after "FL" 

and uses the following format:

NWS NATIONAL HURRICANE CENTER MIAMI FL BBCCYYYY

where:

BB = Ocean Basin

AL - North Atlantic basin...north of the Equator

SL - South Atlantic basin...south of the Equator

EP - North East Pacific basin...eastward of 140oW

CP - North Central Pacific basin between the Dateline and 140oW

WP - North West Pacific basin...westward of the Dateline

IO - North Indian Ocean basin...north of the Equator between 40oE and 100oE

SH - South Pacific Ocean Basin and South Indian Ocean basin

CC= Cyclone Number

Numbers 01 through 49 are reserved for tropical and subtropical cyclones. A cyclone 

number is assigned to each tropical or subtropical cyclone in each basin as it develops. 

The numbers are assigned in chronological order.

Numbers 50 through 79 are reserved for internal use by operational forecast centers.

Numbers 80 through 89 are reserved for training, exercises and testing.

Numbers 90 through 99 are reserved for tropical disturbances which have the potential 

to become tropical or subtropical cyclones. Although not required, the 90’s should be 

assigned sequentially and reused throughout the calendar year.

YYYY=Four-digit year

This is the calendar year for the Northern Hemisphere. For the Southern Hemisphere, 

the year begins July 1, with calendar year plus one.

[Note: Tropical cyclone public advisories issued by the NHC, CPHC, and WFO Guam will 

contain appropriate information as shown in the example in Figure 4-2.]

4.3.3.1. Definition of Wind Radii by Quadrant.

The working definition of the wind radius for a quadrant is: use the largest radius of that wind 

speed found in the quadrant. Example: NHC's quadrants are defined as NE (0°-90°), SE 

(90°-180°), SW (180°-270°), and NW (270°-360°). Given a maximum 34-knot radius of 150 
4-3

nautical miles (nm) at 0°, 90 nm at 120°, and 40 nm at 260°, the following line would be carried in 

the forecast/advisory: 150NE 90SE 40SW 150NW.

4.3.3.2. Numbering of Tropical and Subtropical Cyclone Forecast/ Advisories. All 

tropical cyclone forecast/advisories for each unique system in the Atlantic and Pacific will be 

numbered sequentially beginning with the number 1. Some examples are listed below:

Subtropical Depression ONE Forecast/Advisory Number 1

Tropical Depression ONE Forecast/Advisory Number 1

Tropical Depression ONE Forecast/Advisory Number 2

Tropical Storm Anita Forecast/Advisory Number 3

Hurricane (Typhoon) Anita Forecast/Advisory Number 4

Tropical Depression Anita Forecast/Advisory Number 5
4-4

ZCZC MIATCMAT4 ALL

TTAA00 KNHC DDHHMM

HURRICANE IKE FORECAST/ADVISORY NUMBER 42

NWS NATIONAL HURRICANE CENTER MIAMI FL AL092008

1500 UTC THU SEP 11 2008

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

A HURRICANE WARNING HAS BEEN ISSUED FROM MORGAN CITY LOUISIANA TO BAFFIN BAY TEXAS.

A TROPICAL STORM WARNING HAS BEEN ISSUED FROM SOUTH OF BAFFIN BAY TO PORT MANSFIELD TEXAS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A HURRICANE WARNING IS IN EFFECT FOR...

* MORGAN CITY LOUISIANA TO BAFFIN BAY TEXAS 

A TROPICAL STORM WARNING IS IN EFFECT FOR...

* EAST OF MORGAN CITY TO THE MISSISSIPPI-ALABAMA BORDER...INCLUDING 

THE CITY OF NEW ORLEANS AND LAKE PONTCHARTRAIN

* SOUTH OF BAFFIN BAY TO PORT MANSFIELD

HURRICANE CENTER LOCATED NEAR 25.5N 88.4W AT 11/1500Z

POSITION ACCURATE WITHIN 10 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 9 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 945 MB

MAX SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT.

64 KT.......100NE 100SE 30SW 60NW.

50 KT.......150NE 150SE 90SW 140NW.

34 KT.......230NE 240SE 150SW 180NW.

12 FT SEAS..330NE 240SE 240SW 400NW.

WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL

MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 25.5N 88.4W AT 11/1500Z

AT 11/1200Z CENTER WAS LOCATED NEAR 25.3N 88.0W

FORECAST VALID 12/0000Z 25.9N 90.0W

MAX WIND 90 KT...GUSTS 110 KT.

64 KT...100NE 100SE 30SW 60NW.

50 KT...150NE 150SE 90SW 140NW.

34 KT...230NE 240SE 150SW 180NW.

FORECAST VALID 12/1200Z 26.6N 92.0W

MAX WIND 95 KT...GUSTS 115 KT.

64 KT...100NE 100SE 50SW 60NW.

50 KT...150NE 150SE 90SW 140NW.

34 KT...230NE 240SE 150SW 180NW.

FORECAST VALID 13/0000Z 27.8N 94.2W

MAX WIND 105 KT...GUSTS 130 KT.

64 KT...100NE 100SE 50SW 60NW.

50 KT...150NE 150SE 90SW 120NW.

34 KT...230NE 240SE 150SW 160NW.

FORECAST VALID 13/1200Z 29.5N 95.9W...INLAND

MAX WIND 100 KT...GUSTS 120 KT.

50 KT...120NE 125SE 75SW 90NW.

34 KT...180NE 240SE 120SW 120NW.

FORECAST VALID 14/1200Z 34.5N 94.0W...INLAND

MAX WIND 35 KT...GUSTS 45 KT.

34 KT... 75NE 75SE 50SW 50NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 225 NM

ON DAY 4 AND 300 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 15/1200Z 38.0N 85.0W...POST-TROP/EXTRATROP

MAX WIND 25 KT...GUSTS 35 KT.

OUTLOOK VALID 16/1200Z...ABSORBED

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 25.5N 88.4W

NEXT ADVISORY AT 11/2100Z

$$

FORECASTER FRANKLIN

Figure 4-1. Tropical Cyclone Forecast/Advisory Format

[Note: NWS text products are limited to 69 characters per line. For the example above (Figure 4-1), there are more 

than 69 characters on some lines so the example could fit on one page.]
4-5

ZCZC MIATCPAT1 ALL

TTAA00 KNHC DDHHMM

BULLETIN

TROPICAL STORM ANA ADVISORY NUMBER 6

NWS NATIONAL HURRICANE CENTER MIAMI FL AL012015

500 AM EDT SAT MAY 09 2015

...ANA TRANSITIONS TO A TROPICAL STORM WHILE IT MOVES SLOWLY

NORTH-NORTHWESTWARD TOWARD THE CAROLINAS...

SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION

----------------------------------------------

LOCATION...32.4N 77.6W

ABOUT 105 MI...170 KM SSE OF CAPE FEAR NORTH CAROLINA

ABOUT 115 MI...190 KM SE OF MYRTLE BEACH SOUTH CAROLINA

MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H

PRESENT MOVEMENT...NNW OR 340 DEGREES AT 3 MPH...6 KM/H

MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES

WATCHES AND WARNINGS

--------------------

CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...

* South Santee River South Carolina to Cape Lookout

A Tropical Storm Watch is in effect for...

* Edisto Beach South Carolina to South of South Santee River

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area, in this case within 12-24 

hours.

A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case within 24 hours.

Interests elsewhere in eastern North Carolina should monitor the progress of Ana.

For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your

local National Weather Service forecast office.

DISCUSSION AND 48-HOUR OUTLOOK

------------------------------

At 500 AM EDT (0900 UTC), the center of Tropical Storm Ana was located near latitude 32.4 North, longitude 77.6 West. Ana is moving

toward the north-northwest near 3 mph (6 km/h). A turn toward the northwest and then back to the north at a slightly faster forward

speed is expected over the next 48 hours. On the forecast track, the center will be near the coasts of South and North Carolina by

Sunday morning. Data from NOAA Doppler weather radars indicate that maximum sustained winds are near 60 mph (95 km/h) with higher gusts.

Although Ana has made the transition to a tropical storm, little additional strengthening is forecast through today. A gradual weakening 

trend is expected to begin by tonight or Sunday morning.

Tropical-storm-force winds extend outward up to 125 miles (205 km) from the center. During the past couple of hours, the Frying Pan

Shoals NOAA buoy measured a sustained wind of 41 mph (66 km/h) and a gust to 56 mph (91 km/h).

The estimated minimum central pressure is 998 mb (29.47 inches).

HAZARDS AFFECTING LAND

WIND: Tropical storm conditions are expected within the warning area, and possible within the watch area, by this afternoon or evening.

STORM SURGE: The combination of storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters.

The water could reach 1 to 2 ft above ground at times of high tide in coastal areas from Cape Hatteras, North Carolina southward through 

South Carolina. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Tropical Storm Ana is expected to produce rainfall accumulations of 1 to 3 inches, with isolated amounts of 5 inches, over 

eastern portions of North Carolina and South Carolina through Monday.

SURF: Swells generated by Ana are affecting portions of the southeastern U.S. coast. These swells will likely cause life-threatening 

surf and rip currents. Please see statements issued byyour local National Weather Service forecast office.

NEXT ADVISORY

-------------

Next intermediate advisory at 800 AM EDT.

Next complete advisory at 1100 AM EDT.

$$

Forecaster Stewart

NNNN

Figure 4-2. Tropical Cyclone Public Advisory Format

[Note: NWS text products are limited to 69 characters per line. For the example above (Figure 4-2), there 

are more than 69 characters on some lines so the example could fit on one page.]
4-6
5-1 

CHAPTER 5: AIRCRAFT RECONNAISSANCE

5.1. General. 

All Department of Commerce (DOC) tropical and subtropical cyclone aircraft reconnaissance 

needs will be requested and provided in accordance with the procedures of this chapter. DOC has 

identified a requirement for, and the Department of Defense (DOD) maintains aircraft to support, 

up to five sorties per day. Requirements exceeding five sorties will be accomplished on a 

"resources-permitting" basis. In times of national emergency or war, some or all DOD 

reconnaissance resources may not be available to fulfill DOC needs. The Global Decision Support 

System (GDSS) JCS Priority Code for tasked, operational weather reconnaissance is 1A3 (IAW 

DOD Regulation 4500.9-R and Joint Publications 4-01 and 4-04). The Force Activity Designator 

(FAD)/Urgency of Need Designator (UND) Supply Priority Designator Determination code is 

IIA2 (IAW Joint Publication 4-01 and Air Force Manual 23-110, Volume 2, Part 13, Attachment 

3A-2.) 

5.2. Responsibilities.

The DOD, through the AFRC's 53rd Weather Reconnaissance Squadron (53 WRS), and DOC, 

through NOAA's Aircraft Operations Center (AOC), operate a complementary fleet of aircraft to 

conduct hurricane/tropical cyclone reconnaissance, synoptic surveillance, and research missions. 

5.2.1. DOD.

The DOD is responsible for: 

5.2.1.1. Providing operational aircraft for vortex fixes and data, synoptic surveillance missions, 

and investigative flights in response to DOC needs (see Figure 5-1).

5.2.1.2. Developing operational procedures and deploying data buoys to satisfy DOC needs. 

5.2.1.3. Maintaining the capability of operating from two (2) deployed locations, as well as from 

home station, simultaneously. 

5.2.2. DOC. 

The DOC is responsible for aircraft operations that may be requested to: 

5.2.2.1. Provide vortex fixes, acquire airborne radar data, and conduct synoptic surveillance 

missions (see Figure 5-2). 

5.2.2.2. Augment AFRC aircraft reconnaissance when DOC needs exceed the capabilities of 

DOD resources (see Figure 5-2).

5.2.2.3. Assume responsibility for hurricane reconnaissance over foreign airspace that may be 

restricted for military operations.

5.2.2.4. Conduct research flights. 

5.2.3. DOT.

The DOT is responsible for providing air traffic control services to aircraft when within airspace 

controlled by the FAA. This includes offshore oceanic airspace. Procedures for the expeditious 

handling of reconnaissance aircraft are documented in chapter 6, Airspace Operations.
5-2 

Figure 5-1. WC-130J Weather Reconnaissance Aircraft

Figure 5-2. NOAA G-IV and WP-3D Weather Surveillance/Hurricane Aircraft

5.3. Control of Aircraft. 

Operational control of aircraft flying tropical and subtropical cyclone reconnaissance will remain 

with the operating agencies which own the aircraft.

5.4. Reconnaissance Requirements.

5.4.1. Meteorological Parameters.

Data needs in priority order are as follows: 

• Geographical position of the flight level vortex center (vortex fix) and relative position of the 

surface center, if known. 

• Wind data (continuous observations along the flight track) for surface and flight level. 

• Center sea-level pressure determined by dropsonde or extrapolation from within 1,500 ft of the 

sea surface or from the computed 925 mb, 850 mb, or 700 mb height. 

• Minimum 700, 850 or 925 mb height, if available. 

• SFMR surface wind and rain rate.
5-3 

• Radar reflectivity imagery. 

• High density three-dimensional Doppler radial velocities of the tropical cyclone 

core circulation. 

• Temperature at flight level. 

• Sea-surface temperature. 

• Dew-point temperature at flight level.

5.4.2. Accuracy.

5.4.2.1. Geographic Position.

• Aircraft position: within 3 nm.

• Storm surface center (wind/pressure): within 6 nm. 

• Flight level storm center (wind/pressure): within 6 nm.

5.4.2.2. Wind Direction.

• Surface: within 10 deg. 

• Flight level for winds greater than 20 kt: within 5 deg. 

5.4.2.3. Wind Speed.

• Surface: within 10 kt. 

• Flight level: within 4 kt.

5.4.2.4. Pressure Height.

• Surface: within 2 mb. 

• Flight level at or below 500 mb: within 10 m.

• Flight level above 500 mb: within 20 m. 

5.4.2.5. Temperature.

• Sea surface: within loC.

• Flight level: within loC.

5.4.2.6. Dew-Point Temperature.

• From 20oC to +40°C: within loC. 

• Less than 20oC: within 3oC. 

5.4.2.7. Absolute Altitude: Within 10 m. 

5.4.2.8. Vertical Sounding.

• Pressure: within 2 mb. 

• Temperature: within 1oC. 

• Dew-point temperature: 

• From 20oC to +40oC: within loC. 

• Less than 20oC: within 3oC. 

• Wind direction: within 10 deg. 
5-4

• Wind speed: within 5 kt.

5.4.2.9. Core Doppler Radar.

• Horizontal resolution along aircraft track: 1.5 km 

• Radar beam width: 3 degrees.

• Radar radial resolution (gate length): 150 m.

• Error in radar radial velocity: 1 m/s.

• Range: 50 km.

[NOTE: Present weather reconnaissance capabilities do not completely satisfy these 

requirements; data will be collected as close to stated requirements as possible.]

5.4.3. High-Density/High-Accuracy (HD/HA) Data Requirements. 

The HD/HA data include UTC time, aircraft latitude, longitude, static pressure, geopotential 

height, extrapolated sea level pressure or D-Value, air temperature, dew point temperature, 

flight-level (FL) wind direction, FL wind speed, peak 10-second (10-s) average FL wind speed, 

peak 10-s average surface wind speed from the stepped frequency microwave radiometer (SFMR), 

SFMR-derived rain rate, and quality control flags. Except for the peak values noted above, all data

provided in HDOB messages are 30-second averages, regardless of the interval at which the 

HDOB messages are reported. See Appendix G for HDOB message formats. The DOC requires 

rapid acquisition and transmission of tropical cyclone data, especially within the 24-hour period 

prior to landfall. If HD/HA capability is lost on an operational mission, the airborne meteorologist 

will immediately contact Chief, Aerial Reconnaissance Coordination, All Hurricanes (CARCAH) 

to determine data requirements for the remainder of the mission.

5.4.4. Synoptic Surveillance Data Requirements. 

When required, NHC will request sounding data on the periphery of systems approaching 

populated areas. CPHC may request sounding data on the periphery of those that may impact the 

Hawaiian Islands. For all synoptic-surveillance tasking requirements, NHC will be responsible for 

providing specific tracks including control points, control times and dropwindsonde locations to 

CARCAH for coordination with the reconnaissance units.

5.4.5. Core Doppler Radar Requirements. 

When required, NHC and the Environmental Modeling Center (EMC) will coordinate to request 

high-density three- dimensional Doppler radial velocities in the tropical cyclone core for potential 

storms impacting the United States, including Puerto Rico and the Virgin Islands. EMC, NHC, and 

HRD will coordinate to provide specific flight plans to CARCAH for coordination with the 

reconnaissance units.

5.4.6. Required Frequency and Content of Observations. 

Observation requirements are summarized in Table 5-1. Deviations to these requirements will be 

coordinated through CARCAH. The Vortex message format and information are shown in Figure 

5-3, Figure 5-4, and Table 5-2. Other data message formats and code breakdowns can be found in 

Appendix G. Inner core radar reflectivity should be provided at a rate of one image per TC fix and 

sent to CARCAH and duty forecasters at NHC or CPHC ideally within 30 minutes of transmission 

of each corresponding Vortex Data Message if aircraft communications systems are capable. 
5-5 

Table 5-1. Requirements for Aircraft Reconnaissance Data

RECCO Section 1

plus 4ddff and 9VTTT as 

applicable

Vortex Data

Message 

(VDM)

Vertical Data WMO 

Temp Drop Code

(FM37-VII)

High Density

Observation

(HDOB)

En route

Approx. every 30 minutes 

over water not to exceed 

200 nm

NA

Approx every 400 nm 

over water, or 

fewer/relocated per 

request or sonde 

conservation

30-sec interval 

Invest area

At major turnpoints. Also, 

every 15 minutes if HDOBs 

are INOP.

After closing a 

circulation NA 30-sec interval 

Fix pattern

End points of Alpha pattern 

legs.

When necessary with radar 

fix information.

Each fix.

Each tasked fix at or 

above 850 mb.

Intermediate fixes and 

eyewall modules as 

requested.

30-sec interval 

5.4.7. WP-3D Configuration. 

The minimum operational configuration of the WP-3D will include the stepped frequency 

microwave radiometer (SFMR), Doppler radar and the advanced vertical atmospheric profiling 

system (AVAPS).

5.5. Reconnaissance Planning and Flight Notification.

5.5.1. DOC Requests for Aircraft Reconnaissance Data.

5.5.1.1. Coordination. Any NOAA/NWS facility requesting aircraft reconnaissance (e.g., the 

NWS Environmental Modeling Center (EMC), the Central Pacific Hurricane Center (CPHC)) 

should contact the National Hurricane Center (NHC) no later than 1630 UTC the day prior to the 

requirement, and within the constraints of paragraph 5.5.2.1. NHC will compile the list of the total 

DOC requirements for data on tropical and subtropical cyclones or disturbances for the next 

24-hour period (1100 to 1100 UTC) and an outlook for the succeeding 24-hour period. This 

coordinated request will be considered the agency’s request for assistance (RFA) to DOD and will 

be provided to CARCAH as soon as possible, but no later than 1630 UTC each day in the format of 

Figure 5-5 

5.5.1.2. Tropical Cyclone Plan of the Day. From the coordinated DOC request, CARCAH 

will publish the Tropical Cyclone Plan of the Day (TCPOD). The format for the TCPOD is shown 

in Figure 5-6. When DOC reconnaissance needs exceed DOD and DOC resources, CARCAH will 

coordinate with the NHC to establish priorities of requirements. 
5-6 

DATE SCHEDULED FIX TIME AIRCRAFT 

NUMBER ARWO

WX MISSION IDENTIFICATION STORM NUMBER IDENTIFIER OB

VORTEX DATA MESSAGE

A Z DATE AND TIME OF FIX

B 

DEG MIN N S LATITUDE OF VORTEX FIX

DEG MIN E W LONGITUDE OF VORTEX FIX

C MB M MINIMUM HEIGHT AT STANDARD LEVEL

D KT ESTIMATE OF MAXIMUM SURFACE WIND OBSERVED

E DEGNM BEARING AND RANGE FROM CENTER OF MAXIMUM SURFACE WIND

F DEGKT MAXIMUM FLIGHT LEVEL WIND NEAR CENTER

G DEGNM BEARING AND RANGE FROM CENTER OF MAXIMUM FLIGHT LEVEL WIND

H 

MB MINIMUM SEA LEVEL PRESSURE COMPUTED FROM DROPSONDE OR 

EXTRAPOLATED FROM FLIGHT LEVEL. IF EXTRAPOLATED, CLARIFY IN 

REMARKS.

I C/ M MAXIMUM FLIGHT LEVEL TEMP/PRESSURE ALTITUDE OUTSIDE EYE

J C/ M MAXIMUM FLIGHT LEVEL TEMP/PRESSURE ALTITUDE INSIDE EYE

K C/ C DEWPOINT TEMP/SEA SURFACE TEMP INSIDE EYE

L EYE CHARACTER: Closed wall, poorly defined, open SW, etc.

M 

EYE SHAPE/ORIENTATION/DIAMETER. CODE EYE SHAPE AS: C -Circular; CO - 

Concentric; E- Elliptical. TRANSMIT ORIENTATION OF MAJOR AXIS IN TENS OF 

DEGREE (i.e., 01-010 to 190; 17-170 to 350). TRANSMIT DIAMETER IN NAUTICAL 

MILES. Examples: C8 - Circular eye 8 miles in diameter. EO9/15/5 - Elliptical eye, 

major axis 090-270, length of major axis 15 NM, length of minor axis 5NM. CO8-14 - 

Concentric eye, diameter inner eye 8 NM, outer eye 14 NM.

N 

FIX DETERMINED BY/FIX LEVEL. FIX DETERMINED BY: 1 - Penetration; 2 - Radar; 

3 - Wind; 4 - Pressure; 5 - Temperature. FIX LEVEL: Indicate surface center if visible; 

indicate both surface and flight level centers only when same: 0 - Surface; 1 - 1500ft; 

9-925mb; 8 - 850 mb; 7 - 700 mb; 5 - 500 mb; 4 - 400 mb; 3 - 300 mb; 2 - 200 mb; NA -

Other.

O NM NAVIGATION FIX ACCURACY/METEOROLOGICAL ACCURACY

P 

REMARKS

MAX FL WIND_________________KT_________BEARING / RANGE NM_____________________Z

MAX OUTBOUND FL WIND_________________KT_________BEARING / RANGE NM___________Z

MAX OUTBOUND AND MAX FL WIND ____ KT ____ BEARING / RANGE NM ______Z

CNTR DROPSONDE SFC WIND / KT

SLP EXTRAP FROM (Below 1500 FT/ 925 MB/ 850 MB/ 700 MB/ DROPSONDE)

SFC CNTR__________________________/______________NM FROM FL CNTR

MAX FL TEMP _________C___________/___________NM FROM FL CNTR

SURFACE WIND OBSERVED VISUALLY

INSTRUCTIONS: Items A through G (and H when extrapolated) are transmitted from the aircraft immediately following the fix. The 

remainder of the message is transmitted as soon as available.

Figure 5-3. Vortex Data Message Worksheet
5-7 

Table 5-2. Vortex Data Message Entry Explanation

DATA ITEM ENTRY

Mission Identifier As determined in Chapter 5, paragraph 5.7.7.

Storm Identifier As determined in Chapter 4, paragraph 4.3.3.

Observation Number A two digit number determined by the sequential order in which the observation is 

transmitted from the aircraft.

A (ALPHA) Date and time (UTC) of the flight level center fix. If the flight level center cannot be fixed 

and the surface center is visible, enter the time of the surface center fix.

B (BRAVO) The latitude and longitude of the center fix associated with item ALPHA. NOTE: If the 

surface center is fixable, enter bearing and range from the FL center in Remarks; e.g., SFC 

CNTR 270/15 nm, if the centers are separated by over 5 nm.

C (CHARLIE) Indicate the standard atmospheric surface e.g. 925, 850 or 700 mb. The minimum height of 

the standard surface observed inside the center. If at 1,500 ft or below or not within 1,500 ft 

of a standard surface, enter NA.

D (DELTA) The maximum surface wind observed during the inbound leg associated with this fix. When 

SFMR surface wind data are unavailable, the surface wind is determined visually.

E (ECHO) Bearing and range of the maximum surface wind observed (item DELTA) from the 

coordinates reported in item BRAVO.

F (FOXTROT) The maximum flight level wind observed during the inbound leg associated with this fix. If 

a significant secondary maximum wind is observed, report it in remarks. All winds reported 

should be 10-s averages.

G (GOLF) Bearing and range of the maximum flight level wind observed (item FOXTROT) from the 

coordinates reported in item BRAVO.

H (HOTEL) The minimum sea level pressure (SLP) to the nearest millibar observed at the coordinates 

reported in item BRAVO. Preface the SLP with "EXTRAP" (extrapolated) when the data 

are not derived from dropsonde or when the SLP is extrapolated from a dropsonde that 

terminated early. Clarify the difference in remarks (e.g., “SLP EXTRAPOLATED FROM 

BELOW 1,500 FEET/925 MB/850 MB/700 MB/DROPSONDE”).

I (INDIA) MAX FLT LVL TEMP--This temperature is taken just outside the central region of a 

cyclone (i.e., just outside the eyewall or just beyond the maximum wind band). This 

temperature may not be the highest recorded on the inbound leg but is representative of the 

environmental temperature just outside the central region of the storm.

PRESSURE ALT--Pressure altitude data (meters) are taken at the same location as the 

maximum temperature data reported in item INDIA.
5-8 

Table 5-2 (continued). Vortex Data Message Entry Explanation

DATA ITEM ENTRY

J (JULIET) MAX FLT LVL TEMP--The maximum temperature observed within 5 nm of the center fix 

coordinates. If a higher temperature is observed at a location more than 5 nm away from the 

flight level center (item BRAVO), it is reported in Remarks, including bearing and distance 

from the flight level center.

PRESSURE ALT--Pressure altitude data (meters) are taken at the same location as the 

maximum temperature data reported in item JULIET.

K (KILO) Dewpoint temperature/sea surface temperatures are collected at the same location as the 

maximum temperature reported in item JULIET. Enter NA if not observed.

L (LIMA) Only report if at least 50 percent of the center has an eyewall, otherwise enter NA.

Closed wall--if the center has 100 percent coverage with no eyewall weakness.

Open XX--if the center has 50 percent or more but less than 100 percent coverage. State the 

direction of the eyewall weakness. 

Spiral band--report Item Juliet with the best approximation of the shape/diameter of the 

inner core. 

M (MIKE) Self-explanatory. Report only if item LIMA is reported, otherwise enter NA.

N (NOVEMBER) Fix determined by: Always report 1. Report 2 if radar indicates curvature or banding 

consistent with fix location. Report 3 if recorded or observed winds indicate a closed center.

Report 4 if the fix pressure is lower than all reported on the inbound leg. Report 5 if the fix 

temperature is at least higher than any reported on the inbound leg.

Fix level: Report 0 alone if fix is made solely on surface winds. Report 0 and the flight-level 

code if the centers are within 5 nm of each other.

O (OSCAR) Navigational and meteorological accuracy are reported as the upper limit of probable error. 

Meteorological accuracy is normally reported as one-half of the diameter of the light and 

variable wind center.

P (PAPA) Remarks to enhance the data reported above. Required remarks include: (1) mission 

identifier and observation number; (2) the maximum flight level wind observed, time of 

observation, and the bearing and range from the flight level center of the observed wind on 

the latest pass through any octant of the storm, i.e., 337.5-22.5 degrees, 22.5-67.5 degrees, 

etc.; (3) the maximum flight-level wind observed on the outbound leg following the center 

fix just obtained, if it is higher than the inbound maximum reported in item F. Include time 

of observation and the bearing and range from the flight level center of the qualifying 

outbound max wind. If, after the transmission of the vortex message but prior to the aircraft 

reaching the cross-leg turn point, a higher qualifying outbound wind is observed, then the 

vortex message will be amended with the higher outbound wind reported. If the outbound 

max FL wind becomes the new overall max FL wind, then consolidate the two max FL 

wind remarks into one remark: 

MAX FL WIND 73 KT 081 / 25 NM 23:30:30Z

MAX OUTBOUND FL WIND 55 KT 083 / 14 NM 01:36:00Z

MAX OUTBOUND AND MAX FL WIND 55 KT 083 / 14 NM 01:36:00Z

(4) surface wind direction and speed from the center dropsonde, if available:

CNTR DROPSONDE SFC WIND 265 / 12 KT

(5) the method of deriving the central SLP when extrapolated; and (6) the bearing and range 

of the surface center and/or maximum flight level temperature if not within 5 nm of the 

flight level center. 
5-9 

Figure 5-4. Example Vortex Data Message (VDM) for the WC-130J

URNT12 KNHC 072030

VORTEX DATA MESSAGE AL092008

A. 07/20:09:20Z 

B. 21 deg 01 min N 

 074 deg 26 min W 

C. 700 mb 2624 m 

D. 90 kt 

E. 045 deg 13 nm 

F. 147 deg 106 kt 

G. 047 deg 016 nm 

H. 945 mb 

I. 10 C/ 3045 m 

J. 16 C/ 3057 m

K. 13 C/ NA 

L. CLOSED WALL

M. CO16-48 

N. 12345/7 

O. 0.02 / 1 nm 

P. AF307 0909A IKE OB 11

MAX FL WIND 107 KT 135 / 20 NM 18:21:10Z 
5-10

NHOP COORDINATED REQUEST FOR AIRCRAFT RECONNAISSANCE

___ Original 

___ Amendment 

 (Check One) 

I. ATLANTIC REQUIREMENTS

STORM NAME FIX OR ON

DEPRESSION # STATION FLIGHT FCST NHC

SUSPECT AREA TIME COORDINATES PATTERN MVMT PRIORITY 

___________________________________________________________________________________________________

___________________________________________________________________________________________________

___________________________________________________________________________________________________

GULF STREAM _____________________________________________________________________________________

SUCCEEDING DAY OUTLOOK _______________________________________________________________________

___________________________________________________________________________________________________

REMARKS _________________________________________________________________________________________

___________________________________________________________________________________________________

II. PACIFIC REQUIREMENTS

STORM NAME FIX OR ON

DEPRESSION # STATION FLIGHT FCST NHC

SUSPECT AREA TIME COORDINATES PATTERN MVMT PRIORITY 

___________________________________________________________________________________________________

___________________________________________________________________________________________________

___________________________________________________________________________________________________

SUCCEEDING DAY OUTLOOK _______________________________________________________________________

___________________________________________________________________________________________________

 REMARKS _________________________________________________________________________________________

___________________________________________________________________________________________________

III. DISTRIBUTION

A. TO CARCAH BY 1630Z OR AMEND AT ANY TIME

B. Date ___________ Time _________ FCSTR INITIAL __________

C. 53 WRS ________ AOC _________ Other __________

Figure 5-5. NHOP Coordinated Request for Aircraft Reconnaissance
5-11

TROPICAL CYCLONE PLAN OF THE DAY FORMAT

ATLANTIC AND CENTRAL PACIFIC OCEANS

NOUS42 KNHC ________ (DATE/UTC TIME)

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL

_____ (LOCAL TIME) ___ (TIME ZONE) ___ (DAY) ___ (MONTH/DATE), ____ (YEAR)

SUBJECT: TROPICAL CYCLONE PLAN OF THE DAY (TCPOD)

VALID ______Z (MONTH) TO ______Z (MONTH) (YEAR) 

TCPOD NUMBER.........(YR)- __________

I. ATLANTIC REQUIREMENTS

1. (STORM NAME, DEPRESSION, SUSPECT AREA) or (NEGATIVE RECON RQMTS)

FLIGHT ONE (NHC PRIORITY, if applicable)/TEAL or NOAA _____ (number)

A. ___________________________Z FIX/INVEST TIME

B. ___________________________ MISSION IDENTIFIER

C. ___________________________Z DEPARTURE TIME

D. ___________________________ FORECAST POSITION

E. ___________________________Z TIME ON STATION

F. ___________________________ ALTITUDE(S) ON STATION

G. ___________________________ REMARKS (if needed)

 FLIGHT TWO (if applicable, same as FLIGHT ONE)

2. (SECOND SYSTEM, if applicable, same as in 1. above)

3. OUTLOOK FOR SUCCEEDING DAY (NHC PRIORITY, if applicable)

A. POSSIBLE (Aircraft Mission Requirement) NEAR (Location) AT (Time) Z.

II. PACIFIC REQUIREMENTS (Same as in ATLANTIC)

Figure 5-6. Tropical Cyclone Plan of the Day Format
5-12

5.5.1.3. Anticipated Reconnaissance Requests. Reconnaissance requests can be 

anticipated for a forecast or actual storm location.

5.5.1.3.1. For the Atlantic, Gulf of Mexico, Caribbean, and Central Pacific areas, the requests can 

be:

• Up to four 6-hourly fixes per day when a storm is within 500 nm of landfall and west of 

52.5oW in the Atlantic.

• Up to eight 3-hourly fixes per day when a storm is forecast to be within 300 nm of the U.S. 

coast, Hawaiian Islands, Puerto Rico, Virgin Islands, DOD installations, and other DOD assets 

when specified.

• Up to two synoptic surveillance missions per 24-hour period for potentially land-falling 

storms.

5.5.1.3.2. In the Eastern Pacific, reconnaissance missions may be tasked when necessary to carry 

out warning responsibilities.

5.5.1.3.3. Investigative flights may be requested for disturbances in areas defined above, i.e., one 

or two flights per day dependent upon proximity of landfall and upon known or suspected stage of 

development.

5.5.1.3.4. Exceptions may be made when additional reconnaissance is essential to carry out 

warning responsibilities.

5.5.2. DOD and DOC Reconnaissance Aircraft Responsiveness.

5.5.2.1. Requirement Notification. Notification of requirements must proceed 

tasked-on-station time by at least 16 hours plus en route time to the area of concern.

5.5.2.2. Prepositioning. The "Succeeding Day Outlook" portion of the TCPOD provides 

advance notification of requirements and authorizes units to preposition aircraft to forward 

operating locations. For missions requiring prepositioning, the "Succeeding Day Outlook" may 

not provide adequate advance notification. In this situation, an "Additional Day Outlook" may be 

included in the TCPOD to authorize units to preposition aircraft.

5.5.2.3. Resources Permitting. When circumstances preclude the appropriate notification 

lead time, the requirement will be levied as "resources permitting." When a "resources permitting" 

requirement is levied in an amendment, the NHC will indicate the priority of all existing or 

remaining requirements.

5.5.2.4. Emergency Requirement. If a storm develops unexpectedly and could cause a 

serious threat to lives and property within a shorter time than provided for in the paragraphs above, 

CARCAH will contact the reconnaissance units, or higher headquarters, as appropriate, and 

request assistance in implementing emergency procedures not covered in this plan. The NHC and 

CPHC directors have authority to declare an emergency.

5.5.2.5. NOAA WP-3D Availability. At least one WP-3D will be operationally configured (per 

paragraph 5.4.7) and available to respond to requirements within 24-hours from June 1 through 

November 30 annually. A second WP-3D with the same operational configuration will be 

available each hurricane season from July 15 to September 30. When maintenance and 

programmatic considerations permit, the second aircraft could be made available until November 
5-13

30 also. The frequency of flights when two aircraft are available and with present staffing shall be 

every 12 hours.

5.5.3. Reconnaissance Tropical Cyclone Plan of the Day.

5.5.3.1. Preparation. CARCAH will coordinate the TCPOD (Figure 5-6) daily during the 

period from June 1 to November 30 and at other times during the year as required. Transmitted 

TCPODs will be serially numbered each season.

5.5.3.1.1. CARCAH will coordinate the TCPOD with NHC, the 53 WRS, and NOAA AOC 

before publication.

5.5.3.1.1.1. Combatant command headquarters and their air component command headquarters 

will coordinate on missions by reviewing the proposed TCPOD posted at 

http://www.nhc.noaa.gov/recon.php, then click ‘For Tomorrow’ under ‘Plan of the Day.’

5.5.3.1.1.2. The coordinated TCPOD is the agency’s RFA to DOD. Since DOD’s support to 

NOAA is congressionally mandated and funded through the DOD Appropriations Act, the 

coordinated TCPOD is considered a validated and approved RFA.

5.5.3.1.2. The TCPOD will list all DOC/NOAA AOC and DOD required tropical and subtropical 

cyclone operational reconnaissance missions. Research missions will also be listed in the TCPOD 

when provided to CARCAH before transmission time.

5.5.3.1.3. Amendments to the TCPOD will be published only when requirements change. When 

amended, the impact on each listed flight will be identified (i.e., No Change, Change Added, or 

Cancelled).

5.5.3.2. Dissemination. The TCPOD will be made available to appropriate agencies, such as 

FAA, DOD, and NOAA, which provide support to or control of reconnaissance aircraft or are a 

part of the tropical cyclone warning service. Under normal circumstances, the TCPOD will be 

disseminated by 1830 UTC each day including weekends and holidays. If there are no current day 

or succeeding-day reconnaissance requirements, a negative report, which covers the appropriate 

time frame, will be disseminated. Amendments will be disseminated as required.

[NOTE: The TCPOD is disseminated under the header “MIAREPRPD” for AWIPS users 

and “NOUS42 KNHC” for AWDS users. The TCPOD can be accessed via the Internet at the 

National Hurricane Center homepage at www.nhc.noaa.gov; access the Data & Tools drop 

down menu, then click on ‘Aircraft Reconnaissance.’]

5.6. Reconnaissance Effectiveness Criteria.

5.6.1. General. 

Specified reconnaissance times are established to allow sufficient time for the forecaster to analyze 

the data before issuing an advisory. Every effort should be made to obtain data at scheduled times. 

The following criteria will be used to assess reconnaissance mission effectiveness: 

5.6.1.1. Tropical Cyclone Fix Mission.

• ONTIME. The fix is made no earlier than 1 hour before nor later than 1⁄2 hour after scheduled 

fix time.
5-14

• EARLY. The fix is made from 1 hour before scheduled fix time to one-half of the time interval 

to the preceding scheduled fix, not to exceed 3 hours.

• LATE. The fix is made within the interval from 1⁄2 hour after scheduled fix time to one-half of 

the time interval to the succeeding scheduled fix, not to exceed 3 hours.

• MISSED. Data are not obtained within the parameters specified for on-time, early, or late.

[NOTE: Appropriate credit will be given when the aircraft arrives in the requested area but 

is unable to locate a center due to storm dissipation, the absence of a fixable center, or rapid 

movement. Credit will also be given for radar fixes if penetration is not possible due to 

geographic or other flight restrictions.]

5.6.1.2. Tropical Cyclone Investigative Missions.

• ONTIME. An observation must be taken within 250 nm of the specified coordinates by the 

scheduled time.

• LATE. An observation is taken within 250 nm of the specified coordinates after the scheduled 

time but not later than the scheduled time plus 2 hours.

• MISSED. When the aircraft fails to be within the 250 nm of the specific coordinates by the 

scheduled time plus 2 hours or is unable to provide meaningful data.

5.6.1.3. Synoptic Surveillance Missions. 

• SATISFIED. Requirements are considered satisfied upon completion of the assigned track and 

the acquired dropwindsonde data are transmitted from the aircraft prior to the WPC/OPC 

deadline for synoptic analysis.

• MISSED. When the requirements listed above are not satisfied.

5.6.2. Mission Assessment. 

The NHC or CPHC will provide CARCAH a written assessment of the reconnaissance mission 

anytime its timeliness or quality is outstanding or substandard (see Figure 5-7). Mission 

requirements levied as "resources permitting" will not be assessed for timeliness but may be 

assessed for quality of data gathered.

5.6.3. Summaries. 

CARCAH will maintain monthly and seasonal reconnaissance summaries, detailing requirements 

tasked by NHC and CPHC and missions accomplished.
5-15

MISSION EVALUATION FORM

MEMORANDUM FOR: OL-A, 53 WRS/CARCAH

FROM: (Director, NHC, CPHC) . 

SUBJECT: Mission Evaluation

 (Mission Identifier)

PUBLISHED REQUIREMENTS: 

Premission Coordinates (As Updated Prior to TKO)_____________________N___________________W

Flight Pattern __________________________________________________________________________

Mission Requirements Times ______________________________________________________________

RECONNAISSANCE MISSION PERFORMANCE: 

Flight Flown: _____Completely _____Partially _____Other 

Horizontal Data Coverage: _____Complete _____Timely _____Accurate 

 _____Incomplete _____Untimely _____Inaccurate 

Vertical Data Coverage: _____Complete _____Timely _____Accurate 

 _____Incomplete _____Untimely _____Inaccurate 

Requirements Accomplished: _____On Time _____Early _____Late 

 _____Missed 

OVERALL MISSION EVALUATION: 

 OUTSTANDING____________ 

 UNSATISFACTORY____________ FOR:

 COMPLETENESS____________ TIMELINESS____________ ACCURACY____________ 

 EQUIPMENT_______________ PROCEDURES____________ OTHER_______________ 

REMARKS: (Brief but specific)

________________________ 

FORECASTER's SIGNATURE

Figure 5-7. Mission Evaluation Form

5.7. Aerial Reconnaissance Weather Encoding, Reporting, and 

Coordination. 

5.7.1. Vortex Data. 

A Vortex Data Message (Figure 5-4) will be prepared for all fixes, using all observed vortex fix 

information, each time the aircraft penetrates the center. An image of inner core radar reflectivity 

should ideally be acquired at fix time and correspond to each Vortex Data Message.

5.7.2. Aircraft Radar Fix Data.

When proximity to land, air traffic control restriction, or other factors prevent actual penetration of

the vortex by the reconnaissance aircraft, it is permissible to fix the cyclone by radar. Radar fixes 

may be reported in a vortex data message using available observed information or as a remark 

appended to a RECCO observation taken at fix time. The remark stating the type of radar fix and 

quality of the radar presentation is in accordance with chapter 8, paragraph 8.3.2. Two examples 

follow: 
5-16

Example 1: RADAR FIX PSBL CENTER 21.5N 83.0W, POOR RADAR PRESENTATION, 

SPIRAL BAND, MET ACCURACY 15NM

Example 2: RADAR FIX EYE 21 DEG 23 MIN N 78 DEG 42 MIN W GOOD RADAR 

PRESENTATION CIRCULAR EYE DIAM 25 NM OPEN SW.

5.7.3. Peripheral Data. 

Storm penetration and collection of peripheral data will normally begin at the operational altitude 

approximately 105 nm from the center as determined by the flight meteorologist.

5.7.4. Mission Coordination.

Mission coordination for all missions will be accomplished through CARCAH. Meteorological 

discussions for Central Pacific missions may be accomplished directly with the CPHC; however, 

any changes to tasking will be accomplished through CARCAH.

5.7.5. Post-flight Debriefing.

Unless otherwise directed, the flight meteorologist will provide either an airborne or post-flight 

debriefing to the appropriate hurricane center through CARCAH to ensure all observations were 

received and understood.

5.7.6. Aerial Reconnaissance Abbreviated Communications Headings.

Each type of aerial weather-reconnaissance message is assigned designated abbreviated 

communications headings that are dependent on the geographical region. Table 5-3 provides the 

WMO and AWIPS abbreviated headers for each data product.. The WMO header consists of three 

groups. The first has four letters followed by a two-digit product index number. The initial two 

letters of that group indicate the data type: UR for aerial reconnaissance horizontal observations 

and UZ for aerial reconnaissance vertical observations. The next two letters depict the basin of the 

observation: NT for Atlantic, PN for East and Central Pacific, and PA for West Pacific (see Figure 

5-8). The second element of the header has the ground location ICAO at which the message is 

received from the aircraft and subsequently disseminated through channels described in paragraph 

5.9.1. The remaining element is a date-time group with the time listed in UTC. The AWIPS 

product ID contains five letters followed by a product index number. The first three letters indicate 

the message type: REP for standard observations (RECCO, vortex, and dropsonde) and AHO for 

high-density observations. The other two letters depict the basin location using the same 

geographical conventions as the WMO header.

5.7.7. Mission Identifier. 

Aerial weather-reconnaissance messages will include the five-character agency/aircraft indicator 

followed by the CARCAH-assigned mission/storm-system indicator. Table 5-4 summarizes 

elements of the mission identifier.

5.7.8. Storm Identifier <Storm ID>.

To facilitate the automatic ingest into the NHC, CPHC, and DOD tropical cyclone forecast 

computing systems, the storm identifier will be added 3 spaces after the Vortex Data Message title 

(see Figure 5-4) in the following format: Vortex Data Message BBCCYYYY. For the definition 

of BBCCYYYY, see Chapter 4, paragraph 4.3.3.
5-17

5.7.9. Observation Numbering. 

All aerial weather reconnaissance messages will contain the mission identifier followed by an 

observation number as the first mandatory remark. Standard observation messages (RECCO, 

vortex, and dropsonde) will be sequentially numbered in the order they are transmitted from the 

aircraft. The final message will contain a "LAST REPORT" remark. High-density observation 

(HDOB) messages will also be numbered sequentially but separately from the other messages. 

Table 5-3. Summary of Aerial Reconnaissance Data Products and their Associated Headers

PRODUCT WMO HEADER AWIPS ID

RECCO (non-tasked mission)

Atlantic URNT10 ICAO ddhhmm REPNT0

East and Central Pacific URPN10 ICAO ddhhmm REPPN0

West Pacific URPA10 ICAO ddhhmm REPPA0

RECCO (tasked invest, tropical cyclone, or subtropical cyclone mission)

Atlantic URNT11 ICAO ddhhmm REPNT1

East and Central Pacific URPN11 ICAO ddhhmm REPPN1

West Pacific URPA11 ICAO ddhhmm REPPA1

Vortex Data Message

Atlantic URNT12 ICAO ddhhmm REPNT2

East and Central Pacific URPN12 ICAO ddhhmm REPPN2

West Pacific URPA12 ICAO ddhhmm REPPA2

TEMP DROP Code (dropsonde observation)

Atlantic UZNT13 ICAO ddhhmm REPNT3

East and Central Pacific UZPN13 ICAO ddhhmm REPPN3

West Pacific UZPA13 ICAO ddhhmm REPPA3

High-Density Observation

Atlantic URNT15 ICAO ddhhmm AHONT1

East and Central Pacific URPN15 ICAO ddhhmm AHOPN1

West Pacific URPA15 ICAO ddhhmm AHOPA1

NOTE: ICAO is KNHC (National Hurricane Center--primary) or KBIX (Keesler Air Force 

Base--backup) for data messages originating from USAFR/53 WRS aircraft and KWBC (National 

Weather Service HQ) for data messages originating from NOAA or other agency aircraft.
5-18

Figure 5-8. Geographical Basins in Aerial Reconnaissance Abbreviated Headings

Table 5-4. Elements of the Mission Identifier

AGENCY/ 

AIRCRAFT Mission Storm System Indicator

Agency + Aircraft 

Number12

Sequential number 

of mission in this 

storm or WX3

Two-digit depression

number or two letter 

identifier if not a 

depression or greater4

Location

A, E, C, or W5

Storm name or mission 

type (i.e., CYCLONE or 

INVEST)

EXAMPLES

AF306 0201C CYCLONE

USAF aircraft 5306 on the second mission for Tropical or Subtropical 

Depression One in the Central Pacific. Mission type can be fix or 

surveillance, as specified in the TCPOD.

AF307 0403E CARLOS

USAF aircraft 5307 on the fourth mission for the third classified tropical 

or subtropical system that formed in the Eastern Pacific and acquired the 

name Carlos.

NOAA2 01BBA INVEST NOAA aircraft 42RF on the first mission to investigate the second 

unclassified suspect area in the Atlantic, Gulf of Mexico, or Caribbean.

NOAA9 WAWXA AL92 NOAA aircraft N49RF on the first flight of a sequence of non-tasked 

research missions into Atlantic suspect area AL92.

NOAA3 WF13A KARL

NOAA aircraft N43RF on the sixth flight of a sequence of non-tasked 

research missions into the system that developed from suspect area 

AL92 into the thirteenth tropical or subtropical cyclone in the Atlantic 

Basin and acquired the name Karl.

 

1 AF plus last 3 digits of tail number

2 NOAA, plus last digit of aircraft registration number

3

Non-tasked missions will be assigned WX. For sequential research missions into the same system, another letter can 

optionally be substituted for “X,” starting with “A” (e.g., WA, WB, WC, etc.) 

4 The letters CC should not be used in an invest identifier. WX indicates an unclassified system without operational 

invest tasking.

5 A=Atlantic, Caribbean, or Gulf of Mexico; E=Eastern Pacific; C=Central Pacific; W=Western Pacific
5-19

5.7.10 Corrections to Observations. 

A correction indicator should be appended to the WMO abbreviated header after the date/time 

group and to any lines containing the mission identifier and observation number within corrected 

aircraft messages. This includes the first remark line in a RECCO, Item P in a vortex data, each of 

the 61616 lines in a sonde TEMP DROP code, and the second line in an HDOB data message. The 

first corrected message will have an indicator of CCA; subsequent corrections will have indicators 

of CCB, CCC, etc. Examples of corrected observations are in Table 5-5 below:

Table 5-5. Examples of Corrected Observations

EXAMPLES

URNT11 KNHC 111629 CCA

97779 16264 51286 90000 30400 09054 11071 /3136

40545

RMK AF303 2709A IKE OB 01 CCA

Correction for RECCO message OB 01 

from the AF303 02709A IKE mission.

URNT12 KNHC 130552 CCB

VORTEX DATA MESSAGE AL092008

A. 13/04:47:20Z

B. 28 deg 52 min N

094 deg 37 min W

 . 

 . 

 . 

P. AF301 3509A IKE OB 02 CCB

MAX FL WIND 103 KT 135 / 20 NM 04:30:40Z

CORRECTED FOR TIME IN ITEM A

Second correction for vortex data 

message OB 02 from the AF301 3509A 

IKE mission.

UZNT13 KWBC 080739 CCA

XXAA 58062 99300 70760 11606 99/// ///// ///// 00956 25616 09512

 . 

 . 

 . 

61616 NOAA9 1109A IKE OB 03 CCA

62626 0629 LST WND 894 AEV 20704 CORRECTED RPT DLM WND

08509 0071

82 =

XXBB 58068 99300 70760 11606 00/// ///// 11007 26217 22977 24010

 . 

 . 

 . 

61616 NOAA9 1109A IKE OB 03 CCA

62626 0629 LST WND 894 AEV 20704 CORRECTED RPT DLM WND

08509 0071

82 =

Correction for sonde TEMP DROP 

code message OB 03 from the NOAA9 

1109A IKE mission.

5.8. Operational Flight Patterns. 

This section details the operational flight patterns that provide vortex and peripheral data on 

tropical and subtropical cyclones. 

5.8.1. Flight Pattern ALPHA Operational Details.

5.8.1.1. Flight Levels and Sequence. Flight levels will normally be 1,500 ft, 925 mb, 850 

mb, or 700 mb, depending on data requirements and flight safety. Legs will normally be 105 nm 

long and flown on intercardinal tracks (45 degrees off cardinal tracks). The flight sequence is 
5-20

shown in Figure 5-9. The pattern can be started at any intercardinal point and then repeated 

throughout the mission. Prior to starting an inbound or outbound track the aircrew should evaluate 

all available data, e.g., radar presentation, satellite photo, for flight safety. Once started on course, 

every effort should be made to maintain a straight track and the tasked altitude. A horizontal 

observation is required at each leg end point. This data is transmitted immediately. The ALPHA 

pattern may be modified to satisfy unique customer requirements (such as extending legs to 

examine the wind profile of a strong storm) or because of proximity of land or warning areas. 

Figure 5-9. Flight Pattern ALPHA

5.8.1.2. Vortex fix data. On each transit of the center a fix will be made and a vortex data 

message completed, using data gathered on the inbound track since the previous fix and will be 

transmitted immediately. Center dropsonde data will also be provided for scheduled fixes made at 

850 mb or above. The dropsonde will be released at the flight-level center coordinates (item 

BRAVO of the vortex data message). For fixes when dropsonde-measured SLP is not available, an 

extrapolated SLP will be computed and reported. 

5.8.2. Investigative Missions. An investigative mission is tasked on tropical or subtropical 

disturbances to determine the existence or non-existence of a closed circulation, supply 

reconnaissance observations in required areas, and locate the vortex center, if any.

5.8.2.1. Flight Levels. Flight level will normally be at or below 1,500 ft absolute altitude but 

may be adjusted as dictated by data requirements, meteorological conditions, or flying safety 

factors.

5.8.2.2. Vortex Fix. A vortex data message is required if a vortex fix is made.

5.8.2.3. Closed Circulation. A closed circulation is supported by at least one sustained wind 

reported in each quadrant of the cyclone. Surface winds are preferred. 

5.8.2.4. Flight Pattern. The preferred approach is to fly to the tasked coordinates of the 

forecasted center and then execute a pattern as observed conditions dictate. Suggested patterns are 

the X, Box, or Delta patterns, but the flight meteorologist may choose any approach. See Figure 

5-10. Turns are usually made to take advantage of tailwinds whenever possible. Note: The 

depicted pattern may be converted to a mirror image if entry is made from a different direction.

• On the X pattern, the aircraft is turned to head directly towards the center, as indicated by the 

surface or flight level winds. The aircraft is flown through the calm center until winds from the 

opposite direction occur (second quadrant). The aircraft is then turned to a cardinal heading 

until a wind shift occurs (third quadrant). Finally, the aircraft is turned towards the center and 

flown straight through the center to the last quadrant. 
5-21

• On the Box pattern, the aircraft is flown on cardinal headings around the suspected center. The 

track resembles three sides of a square.

• On the Delta pattern, the aircraft is flown on a cardinal heading to pass 60 nm from the 

forecasted center. After observing a wind shift (second quadrant) the aircraft is turned to pass 

through the center until winds from the opposite direction occur (third quadrant). Finally, the 

aircraft is turned on a cardinal heading (parallel to the initial heading) to pick up the fourth 

quadrant winds. If data indicate that the aircraft is far north of any existing circulation, the 

pattern is extended as shown by the dashed lines. 

Figure 5-10. Suggested Patterns for Investigative Missions

5.8.3. Synoptic Surveillance Missions.

A synoptic surveillance mission is tasked to measure the large-scale wind and thermodynamic 

fields within approximately 800 nautical miles of tropical cyclones. Specific flight tracks will vary 

depending on storm location and synoptic situation, and multiple aircraft may be required to 

satisfy surveillance mission requirements.

5.8.4. Eyewall and Outer-Wind Field Sampling Modules. 

These are patterns of dropwindsonde releases designed to measure the maximum surface wind, as 

well as the extent of hurricane and tropical storm force surface winds. They are meant to be flown 

using the operational alpha pattern. Dropwindsonde releases in these modules are in addition to 

any other releases required by Table 5-1. 

5.8.4.1. Eyewall Module. While executing a standard alpha pattern to satisfy a fix requirement, 

one sounding will be taken during each inbound and outbound passage through the eyewall 

(except as noted below), for a total of four soundings. The releases should be made at or just 

inward (within 12 km) of the flight-level radius of maximum wind (RMW). If the radar 

presentation is suitable, the inner edge of the radar eyewall may be used to identify the release 

point. If possible, and when resources and safety permit, two dropwindsondes, spaced less than 30 

seconds apart, should be deployed on the inbound leg on the side of the storm believed to have the 

highest surface winds (normally the right-hand side). In this case, the outer of the two releases 

should be made at the RMW, with the second release following as soon as possible. Typically, the 

eyewall module will be tasked within 48 hours of a forecasted hurricane landfall. 
5-22

5.8.4.2. Outer-Wind Field Module. On an alpha pattern, deploy dropwindsondes at 50 nm 

intervals from the center on each of two successive inbound and outbound legs, outward to 200 

nm. A release should also be made at the midpoint of the cross (downwind) leg, for a total of 19 

soundings, including center drops. The length of the legs and the sounding interval may be 

adjusted, depending on the size of the storm.

5.9. Aircraft Reconnaissance Communications.

5.9.1. General. 

The 53 WRS WC-130 aircraft will normally transmit reconnaissance observations via the Air 

Force Satellite Communications System (AFSATCOM) to a ground station at NHC (primary) or 

Keesler AFB (backup). The CARCAH or 53 WRS mission monitor is responsible for 

quality-controlling the airborne weather-data messages before sending them securely to AFWA's 

Weather Product Management and Distribution System (WPMDS) at Offutt AFB for global 

dissemination. The NOAA G-IV and WP-3D aircraft will normally transmit aircraft messages via 

commercial SATCOM to a secure ingest server that is part of the National Weather Service 

Telecommunications Gateway (NWSTG) located at the NWS Telecommunication Operations 

Center in Silver Spring, MD. Figures 5-11 and 5-12 depict the NOAA and AFSATCOM 

communications links. Flight meteorologists should maintain contact with CARCAH 

continuously throughout the mission to ensure the transmitted data are received and properly 

formatted.

5.9.2. Backup Air-to-Ground Communications. 

The weather reconnaissance crew may relay weather data via SATPHONE or HF phone patch to 

the mission monitor at CARCAH. The monitor will evaluate these reports and disseminate them 

through the WPMDS or to the NWSTG. Specific radio procedures and terminology will comply 

with Allied Communications Publication 125, Standard Telephone and Radio Procedures. The 

NOAA aircraft may optionally send messages to a ground-relay system located at AOC, which, in 

turn, will transfer them to the NWSTG if direct transmission from the aircraft is not possible.
5-23

Figure 5-11. Schematic of WMO Message Path for NOAA G-IV and P-3 Aircraft
5-24

Figure 5-12. Schematic of Aircraft-To-Satellite Data Link for AFRC WC-130 Aircraft

[Note: An Internet link from Keesler AFB to NHC provides the capability for all 

observation types to be passed directly to NHC without going through Offutt Air Force 

Base.] 

Internet link 

 
5-25

5.9.3. Backup CARCAH Procedures. 

Satellite ground stations, which are used to receive and process data from AFRC reconnaissance 

aircraft, are installed at CARCAH (located within NHC) and the 53 WRS (located at Keesler Air 

Force Base). The backup 53 WRS ground station has a similar configuration and communications 

capability as the primary satellite ground station installed at CARCAH. Each ground station can 

fully transmit data using SATCOM or land line to the other ground station. Both can securely send 

reconnaissance aircraft messages to the WPMDS, which then relays them to the NWSTG for 

world-wide distribution, and to an NHC local server (see Figure 5-12). In the event that backup 

procedures are required due to severe communications failures, severe weather conditions, or 

other extreme events affecting NHC, some or all CARCAH responsibilities will be transferred to 

the 53 WRS, ensuring reconnaissance service is uninterrupted.

5.9.3.1. Satellite Antenna Communications Failure at NHC. If an outage is expected to be 

temporary, CARCAH will coordinate with the 53 WRS to have operators man the ground station 

located at Keesler AFB. They will be responsible for maintaining contact with airborne 

reconnaissance aircraft and relaying data via land line to the CARCAH ground station. In the event 

communications lines between Keesler AFB and NHC are also severed, the 53 WRS ground 

station will be configured to transmit data directly to the WPMDS. No procedure is currently 

implemented for sending the aircraft data directly to local servers at WPC or CPHC (NHC’s 

COOP backup site); consequently, all data or observations will need to be accessed from the 

WPMDS or obtained from the NWSTG.

For long-term outages, CARCAH will send personnel to Keesler AFB. They will monitor the 

aircraft data and ensure they are transmitted to the WPMDS, NWSTG, and external users from that 

location.

5.9.3.2. Internet Communications Failure. In the event there is a long-term network 

communications outage between NHC and AFWA, the CARCAH ground station will still be able 

to receive aircraft data and send them to local NHC servers. If Internet access problems originate at 

NHC, the CARCAH ground station will be configured to relay the data to Keesler AFB ground 

station via SATCOM. The 53 WRS ground station will in turn be configured to automatically 

transmit them to the AFWA WPMDS server. However, if the Internet disruptions occur at AFWA, 

no data can be sent to the WPMDS, NWSTG, and external users until service is restored.

5.9.3.3. NHC Emergency Backup Plan. In the event NHC activates the WPC or CPHC 

COOP backup plan, designated CARCAH personnel will deploy to Keesler AFB to operate the 53 

WRS ground station. The reconnaissance data will be obtained at the WPC COOP site either 

through the WPMDS or the NWSTG.
5-26
6-1

CHAPTER 6: AIRCRAFT OPERATIONS

6.1. Mission Coordination.

6.1.1. Administration

6.1.1.1. Annual Liaison Meetings. An annual liaison meeting will be conducted between 

the following participants:

• National Oceanic and Atmospheric Administration (NOAA) Aircraft Operations Center 

(AOC)

• U.S. Air Force Reserve Command (AFRC) 53rd Weather Reconnaissance Squadron (53rd 

WRS)

• Federal Aviation Administration (FAA) Air Traffic Control System Command Center 

(ATCSCC), System Operations Security, and participating en route Air Traffic Control 

(ATC) facilities1

• Department of Defense (DOD) Policy Board on Federal Aviation (PBFA) designated 

representative (optional)

This meeting will review the previous season’s operations, any proposed changes to the current 

NHOP; the trilateral Memorandum of Agreement (MOA) between the FAA Air Traffic 

Organization (ATO), NOAA AOC, and AFRC 53rd WRS2

; supporting Letters of Agreement 

(LOA); arranging FAA familiarization flights; and procedures to conduct international oceanic 

operations in accordance with International Civil Aviation Organization (ICAO) standards and 

recommended practices. This meeting will normally be conducted in conjunction with the Office 

of the Federal Coordinator for Meteorology (OFCM)-sponsored Interdepartmental Hurricane 

Conference (IHC).

6.1.1.2. Visits and Briefings. Annual visits by participating FAA en route ATC facilities, 

System Operations Security, and ATCSCC; and briefings by 53rd WRS aircrews, NOAA AOC 

aircrews, and FAA Military Liaisons are encouraged. These joint visits emphasize the unique 

challenges and non-standard operational procedures, communication and coordination required 

to successfully and safely accomplish the Hurricane Hunter mission.

6.1.1.3. FAA Familiarization Flights. FAA familiarization flights on USAF (IAW AFI 11-

401 and DOD 4515.13) and NOAA Hurricane Hunter aircraft are authorized and encouraged. 

These flights are important in providing FAA controllers with a better understanding of weather 

reconnaissance/research operations, and how to better provide Air Traffic Control (ATC) 

services to these critical flights. These familiarization flights may be requested by FAA 

controllers, in accordance with FAA Order 3120.29, Flight Deck Training Program.

 

1 Specifically includes FAA Air Route Traffic Control Centers (ARTCC), Center Radar Approach Controls (CERAP), and, in select cases, 

Combined Control Facilities (CCF) such as the Honolulu Control Facility (HCF). Only facilities, which have established or intend to establish a 

Letter of Agreement (LOA) in accordance with the national template supporting the trilateral Memorandum of Agreement between the FAA Air 

Traffic Organization, NOAA AOC, and the AFRC 53rd WRS, will participate.

2 Refers to the MOA cited by footnote 1.
6-2

6.1.2. Weather Reconnaissance/Research Aircraft

6.1.2.1. Participating Aircraft. A “Participating Aircraft” for the purposes of the NHOP 

and related documents3 is defined as a NOAA AOC or 53rd WRS manned aircraft listed in the 

Tropical Cyclone Plan of the Day (TCPOD) or tasked with an unscheduled operational mission 

that is conducted in a Weather Reconnaissance Area (WRA).

• 53 WRS: “TEAL 70 through 79” (WC-130J aircraft)

• NOAA AOC: “NOAA 42 and 43” (WP-3D aircraft)

6.1.2.2. Other Weather Reconnaissance/Research Aircraft.

• NASA: “NASA 817” (DC-8 aircraft); “NASA 928” (WB-57 aircraft); “NASA 872” (Global 

Hawk UAS)

• NRL: “WARLOCK 587” (NP-3 aircraft)

• NSF/NCAR: “N677F” (G-V aircraft)

• NOAA AOC: “NOAA 49” (G-IV aircraft)

6.1.2.3. Unmanned Aircraft Systems (UAS) Operations. Unmanned Aircraft Systems 

(UAS) operations are permitted with manned aircraft within a WRA as described in paragraph 

6.2.3.7. No other UAS operations are permitted in a WRA.

6.1.3. Definitions.

6.1.3.1. Mission. For purposes of this chapter, a mission is defined as a flight by an aircraft, 

as described in the NHOP, to conduct weather reconnaissance/research operations.

6.1.3.2. Weather Reconnaissance Area. A Weather Reconnaissance Area (WRA) is 

airspace with defined dimensions and published by Notice to Airmen (NOTAM), which is 

established to support weather reconnaissance/research flights. ATC services are not provided 

within WRAs.4 Only participating weather reconnaissance/research aircraft from NOAA AOC 

and 53rd WRS are permitted to operate within a WRA. A WRA may only be established in 

airspace within U. S. Flight Information Regions (FIRs) outside of U.S. territorial airspace.

6.1.4. Pre-Mission Coordination.

6.1.4.1. Mission Coordination Sheet. All missions must provide a Mission Coordination 

Sheet to the ATCSCC and the affected en route ATC facilities, as soon as possible, but no later 

than 1 hour prior to departure time (see Appendix L).

NOTE- Every effort will be made to accommodate release of SUA. However, in some cases, 

SUA will not be available for release. SUA Using Agencies determine if Department of Defense 

(DOD) operational requirements are compatible with the establishment of a WRA and should 

define de-confliction procedures for SUA that may not be released.

 

3 Including the aforementioned trilateral MOA and any executing LOAs.

4 The FAA may provide ATC services to participating flights in transit to and from WRAs, but will not provide ATC services, specifically 

including separation, to these flights within a WRA.
6-3

6.1.4.2. Chief, Aerial Reconnaissance Coordination (CARCAH). CARCAH’s premission coordination procedures include:

• Publishing TCPOD when required.

• Coordinating with the affected en route ATC facilities and the ATCSCC as required.

• Notifying 53rd WRS and NOAA AOC flight crews when other research missions will be 

airborne in the operations area at the same time.

6.1.4.3. 53rd WRS and NOAA AOC.

• Submit the Mission Coordination Sheet (see Appendix I) according to sub-paragraph 6.1.4.1.

• Submit a request to the appropriate FAA en route ATC facility for a WRA NOTAM.

• Missions Not Listed in the TCPOD. In the event of an unscheduled mission, the flying unit 

will contact the ATCSCC. The ATCSCC will initiate a conference call with the unit and all 

affected ARTCCs.

• Use of NORAD Mode 3/A Transponder Codes. 53rd WRS and NOAA AOC NHOP 

missions may request NORAD assigned mode 3/A transponder codes. These codes are only 

applicable in FAA controlled airspace in the Gulf of Mexico and Atlantic. These codes are 

issued by the 601st Air -Operations Center, Airspace Management Team (DSN 523-5837 or 

COM 850-283-5837) and must be requested as needed.

• If a transponder code is not assigned by NORAD, a code will be assigned by ATC.

6.1.4.4. Flying Agencies (other than the 53 WRS or NOAA AOC).

• NASA, NRL, NSF or any other agency planning reconnaissance/research missions into or 

around the forecast or actual storm location must coordinate with affected FAA en route

ATC facilities and CARCAH as soon as possible prior to all flights.

• The flying unit must submit the Mission Coordination Sheet (see Appendix I) according to 

sub-paragraph 6.1.4.2.

• Flights in support of the NHOP (conducted by the 53rd WRS and NOAA AOC operations) 

are normally published in the TCPOD at http://www.nhc.noaa.gov/reconlist.shtml by 1830 

UTC. Reference the TCPOD to assist in de-confliction efforts.

• Issue advance notification to CARCAH of all planned reconnaissance/research missions in 

areas where NHOP operations are being conducted, including proposed flight tracks, aircraft 

altitudes, and locations where weather instruments may be released; this information can be 

e-mailed to ncep.nhc.carcah@noaa.gov or faxed to 305-553-1901 (please indicate 

“CARCAH” on submitted materials).

NOTE - CARCAH coordination is normally restricted to what is required between the 53 WRS, 

NOAA AOC, NHC, and ARTCCs in support of operational tasking. Due to staffing constraints, 

the CARCAH unit’s operating hours vary and often depend on the requirements levied. Its ability 

to coordinate non-operational missions is extremely limited. Reconnaissance/research missions 

can only be considered on a non-interference basis when flown concurrently with a tasked 

mission or when data collected will be directly beneficial to NHC in real time.

• Transponder codes will be assigned by ATC.
6-4

6.1.4.5. Flight Plan Filing Procedures.

• Flight plans must be filed with the FAA as soon as practicable before departure time.

• For flights into all U.S. Flight Information Regions (FIRs), include delay time in the route 

portion of the international flight plan – this will keep the IFR flight plan active throughout 

operations, especially for a delay in a WRA.

• Only the following remarks should be included in the “Other Information” block:

• “EET” to FIR boundaries,

• Navigation Performance (ex. RNP-10)

• “RMK/MDCN” diplomatic clearance information.

6.1.4.6. Mission Cancellation. When a mission is cancelled or delayed, the unit flying the 

mission must notify the Primary en route ATC facility responsible for the WRA and the 

ATCSCC as soon as possible.

6.1.5. FAA Coordination.

6.1.5.1. Responsibilities. The ATCSCC and the affected en route ATC facilities are 

responsible for operational coordination in support of the NHOP.

6.1.5.2. ATCSCC Procedures.

• Review the TCPOD available at http://www.nhc.noaa.gov/reconlist.shtml, by 1830 UTC.

• Activate the Hurricane desk, if required.

• Review the Mission Coordination Sheet (see Appendix L). Prepare a public Flow Evaluation 

Area (FEA) based on the latitude/longitude points specified in the Mission Coordination 

sheet when a mission is scheduled to be flown. The FEA naming convention is the aircraft 

call sign. Modify the FEA when requested by the affected facilities. (The flying unit will 

submit their Mission Coordination Sheet to the ATCSCC and the affected en route ATC 

facilities at least 1 hour prior to flight departure time).

• Coordinate with the impacted en route ATC facilities as required and designate a primary en 

route ATC Facility when the Operations Area includes airspace managed by multiple ATC 

facilities.

• In the event of an unscheduled mission that is not listed on the TCPOD, the flying unit will 

contact the ATCSCC. The ATCSCC will initiate a conference call with the unit and all 

affected en route ATC facilities.

• When NOAA or TEAL aircraft receive priority handling as specified in FAA Order 7110.65, 

assist en route ATC facilities with traffic flow priorities.

• Conduct hurricane and customer teleconferences, as necessary.

6.1.5.3. En Route ATC Procedures

• Review the TCPOD available at http://www.nhc.noaa.gov/reconlist.shtml, by 1830 UTC.

• Review the Mission Coordination Sheet (see Appendix L) - the flying unit will submit their 

Mission Coordination Sheet to the ATCSCC and affected en route ATC facilities at least 1 

hour prior to flight departure time.

• Coordinate with all impacted en route ATC and Terminal facilities within their area of 
6-5

responsibility.

• Coordinate with all impacted DOD facilities and SUA Using Agencies in accordance with 

Letters of Agreement (LOA), including de-confliction procedures for SUA that may not be 

approved for release.

• When applicable, assign 53rd WRS and NOAA aircraft the designated NORAD transponder 

code associated with their call sign listed on the Mission Coordination Sheet.

• When designated by ATCSCC as the Primary ATC Facility, responsibilities will include:

• Coordinate with CARCAH and aircrew(s) on flight plan specifics, when necessary.

• If the mission profile changes, coordinate with the ATCSCC for FEA modifications, and 

ensure other affected ATC facilities are aware of the change.

• Advise the ATCSCC and other affected ATC facilities of any mission cancellation or 

delay information received from the flying unit.

6.2. Mission Execution.

6.2.1. Aircrew Responsibilities.

6.2.1.1. Aircraft Commander Authority. Aircraft Commanders must exercise their 

authority in the interest of safety or during an aircraft emergency, regardless of NHOP 

procedures.

6.2.1.2. Priority Handling. ATC will provide priority handling to TEAL and NOAA 

aircraft, when requested by the aircrew. The aircraft commander will only ask for priority 

handling when necessary to accomplish the mission.

6.2.1.3. Altitude. Aircrews are responsible for maintaining their own clearance from the 

surface of the sea, obstacles, and oil platforms while operating below the Minimum IFR Altitude 

(MIA).

6.2.1.4. Military Assumes Responsibility for Separation of Aircraft (MARSA).

Aircrews of the 53Rd WRS may apply MARSA, in accordance with FAA Order 7110.65 and 

FAA Order 7610.4, between 53rd WRS aircraft. MARSA may not be applied between 53rd 

WRS aircraft and NOAA AOC participating aircraft.

6.2.1.5. ATC Communications. The aircrew normally maintains ATC communications 

with only the primary ATC Facility. When operating within an ATC terminal area depicted on 

the NHOP Operational Maps (see Appendix K), the aircrews will be in contact with both the 

primary ATC Facility and the terminal facility (FAA or DOD) if it is operating. Normally, VHF, 

UHF or HF radios will be used for communications with ATC, when within range. In the storm 

environment, HF exhibits poor propagation tendencies. When HF is unusable, satellite 

communications (SATCOM) may be used as a back-up (see Appendix L). IFR aircraft flying in 

domestic or international airspace are required to maintain continuous two-way communications 

with ATC, even while flying in uncontrolled airspace (Class F or G). Monitor the active ATC 

radio frequency for any other air traffic transiting the area.

NOTE - While in international airspace, aircrews will make periodic “Operations Normal” 

calls to the primary ARTCC if not in radar contact and no transmissions have been made within 

the previous 20-40 minutes (reference: ICAO 4444/RAC 501/12 VI, 2.1).
6-6

6.2.1.6. Backup ATC Communications Procedures. Aircrews of participating aircraft are 

required to maintain contact with CARCAH at all times. CARCAH is responsible for ensuring 

that ATC clearances, clearance requests and messages are relayed in an accurate manner through 

any means available. Only use this method when the aircraft or ATC is unable to contact each 

other.

6.2.2. NHOP Missions Outside a WRA

6.2.2.1. International Airspace. International airspace is defined as the airspace beyond a 

sovereign State’s 12 NM territorial sea limit. Beyond this limit ICAO rules apply. In 

international airspace, VFR flight is not allowed at night. In class A controlled airspace, aircraft 

must operate using IFR procedures: ATC separation is provided between IFR aircraft. In class E 

controlled airspace, both VFR and IFR operations are allowed; separation is provided between 

IFR aircraft but only traffic and terrain advisories are provided to VFR traffic.

6.2.2.2. IFR Procedures and Clearance. Aircrews will conduct flight operations to and 

from the WRA utilizing IFR procedures to the maximum extent possible and will not normally 

conduct these flight operations under the provisions of “Due Regard.” When departing the WRA, 

if the aircraft commander determines that mission, ATC communications, weather, and/or safety 

requirements dictate, they may exercise their operational prerogative and declare “Due Regard.” 

When conducting “Due Regard” operations, aircrews will comply with as many IFR procedures

as possible. If an aircrew is able to notify ATC before declaring “Due Regard,” ATC will retain 

flight plan information. If an aircrew is unable to notify ATC beforehand, they will inform them 

when able. As soon as practical, the aircrew will notify ATC that they are terminating “Due 

Regard” operations and request resumption of IFR services. These procedures do not preclude 

aircraft commanders from exercising their authority in the interest of safety or during an aircraft 

emergency.

6.2.2.3. Operations in Controlled Airspace. While IFR, and not operating in a WRA, 

ATC will assign an altitude or a block of altitudes and provide standard vertical separation 

between all IFR aircraft and will provide VFR traffic advisories as far as practical. Prior to 

departing controlled airspace, advise ATC and state your intentions; ATC will not cancel your 

IFR flight plan.

6.2.2.4. Operations in Uncontrolled Airspace (Class F and G). Per FAA Order 

7110.65, ATC is not authorized to assign altitudes in nor provide separation between aircraft in 

uncontrolled airspace. While in uncontrolled airspace, the aircraft commander is the IFR 

clearance authority. In addition, aircrews are responsible for maintaining their own separation 

from the surface of the sea, obstacles, and oil platforms while operating below the Minimum IFR 

Altitude (MIA). In class F and G uncontrolled airspace, both VFR and IFR operations are 

allowed. When operating in uncontrolled airspace, flight information service, which includes 

known traffic information, is provided and the pilot is responsible for situating the aircraft to 

avoid other traffic (ICAO, Annex 11).

6.2.3. NHOP Mission Operations in a WRA.

The procedures for participating aircraft operations in a WRA are in accordance with the MOA 

between the FAA, NOAA, and 53 WRS.
6-7

6.2.3.1. General Operations. The airspace within a WRA is normally at or below FL150 

with a radius of 200 NM around a set of center coordinates. An ATC facility prevents nonparticipating aircraft receiving ATC services from entering the WRA during the effective time of 

the WRA as published in the NOTAM. This area can include the terminal areas (Class D 

Airspace) depicted on the NHOP Operational Maps (see Appendix K), and any other airspace 

within 50 NM of the CONUS shoreline after radio contact is established with ATC. If not in 

radar contact within the area as shown on the NHOP Operational Maps (see Appendix K), the 

aircrew will make position reports in relation to designated navigational aids as requested by 

ATC along the coast. Any changes to the WRA will be coordinated with the primary ARTCC.

6.2.3.2. Participating aircraft arrival to a WRA.

• Participating aircraft must use ATC services to the WRA.

• Prior to entering the WRA, the arriving aircraft must obtain the position and altitude of each 

aircraft already in the WRA and verify the center coordinates and maximum radius within the 

WRA.

• Arriving aircraft will commence entry to the WRA from FL1505, unless otherwise 

coordinated with ATC and other participating aircraft.

• Arriving aircraft must report entering the WRA to ATC.

6.2.3.3. Participating Aircraft Procedures in a WRA. The following actions must be 

taken by the aircrews to de-conflict operations and enhance situational awareness with other 

participating aircraft within the WRA:

• Set 29.92 (inches Hg) in at least one pressure altimeter per aircraft.

• Contact (Primary: VHF 123.05 MHz, Secondary: UHF 304.8 MHz, Back-up: HF 4701 KHz) 

the other participating aircraft and confirm (as a minimum) the pressure altitude, location 

relative to a center point position, true heading, and operating altitude or block of altitudes.

• Monitor the frequency during the duration of the flight and maintain communication with all 

other participating aircraft at all times.

• The center coordinates will be used for the duration of the flight. If a WRA is moved due to 

operational reasons, a different center point will be coordinated between all participating 

aircraft.

• If any aircraft is unable to maintain assigned altitude(s), immediately notify all participating 

aircraft and take actions to ensure sufficient vertical and/or lateral separation is maintained or 

attained as soon as practical.

• Use “see and avoid” principles to the maximum extent possible within the WRA. Aircraft 

must periodically broadcast GPS position reports to other aircraft within the WRA and use 

air-to-air TACAN and cockpit displays/maps to maintain awareness of other aircraft 

locations.

6.2.3.4. Separation between participating aircraft within a WRA.

• Aircraft 10 NM or more from other aircraft operating in the same WRA must maintain 

 

5 The upper limit of WRAs may be negotiated between NOAA AOC, 53rd WRS, and the responsible FAA en route ATC. While the default WRA 

will extend from SFC through 15,000 feet, the WRA ceiling may be lowered, especially when established closer to land where ATC services are 

provided at lower altitudes.
6-8

vertical separation within the WRA of at least 1,000 feet between their operating altitudes or 

block altitudes, or as specified in the applicable LOA.

• Aircraft less than 10 NM from other aircraft operating in the same WRA, must apply vertical 

separation of at least 2,000 feet between operating altitudes or block altitudes, or as specified 

in the applicable LOA. Aircraft may use air-to-air TACAN and TCAS to assist with visual 

acquisition. Reduced vertical separation may be applied with concurrence from other aircraft 

within the WRA.

6.2.3.5. Altitude changes between participating aircraft within the WRA.

• Aircraft must initiate communications with each other prior to the altitude change and 

maintain two-way aircraft-to-aircraft communications throughout the duration of the altitude 

change.

• Aircraft must ensure positive lateral separation prior to descending or climbing through the 

altitude(s) of other participating aircraft by reference to the WRA center point using the 

appropriate aircraft navigation systems.

• Aircraft that are not in visual contact and separated by 30 NM or more, as indicated by the 

appropriate aircraft navigation systems, may transition through the altitude of other 

participating aircraft.

• Aircraft that are not in visual contact and separated by less than 30 NM, as indicated by the 

appropriate aircraft navigation systems, must confirm with each other that they are not on 

converging courses prior to an altitude change.

• Aircraft that are in visual contact may apply visual separation in accordance with the 

following procedures:

1. An aircraft that initiates visual separation must advise the other aircraft that the aircraft is in 

sight and will maintain visual separation from it.

2. The observed aircraft must acknowledge the use of visual separation by the initiating aircraft 

prior to the altitude change.

3. The aircraft changing altitude must advise the other aircraft upon reaching and maintaining 

the altitude to which it was climbing or descending.

4. Visual separation may be discontinued when the altitude change is complete.

• An altitude change is complete when the aircraft changing altitude advises the other aircraft, 

and receives an acknowledgement, that the altitude to which it was climbing or descending is 

reached and maintained.

6.2.3.6. Participating aircraft departure from a WRA.

• Prior to departing the WRA, aircraft will establish communications with the appropriate ATC 

facility and request an IFR clearance.

• Aircraft will depart a WRA at FL1406, unless otherwise coordinated with ATC and other 

participating aircraft.

• Prior to departing the WRA, aircraft will verify and maintain vertical and lateral separation 

from other aircraft in the WRA.

 

6 See footnote 5 for information on WRAs with lowered ceilings.
6-9

• Should an aircraft lose communications with the other aircraft within a WRA, it will

maintain the last altitude that was coordinated with the other aircraft until it departs the 

WRA.

• If navigation systems become unreliable, the flight crew will terminate the mission and 

depart the WRA at the last coordinated altitude, or as coordinated with ATC if radio 

communications are available.

• Departing aircraft will report “leaving (tropical activity name) WRA,” to other aircraft in the 

WRA.

NOTE - The tropical activity name is identified by the National Hurricane Center and is part of 

the identification of the WRA. Examples: Isabelle WRA, Sandy WRA, Tropical Storm Emily 

WRA, etc.

6.2.3.7. Weather Instrument Release in a WRA. The aircraft commander is the sole 

responsible party for all weather instrument releases or sensor activations. Aircraft commanders 

will ensure coordination with other participating aircraft prior to release or activation. (Examples 

of weather instruments are dropsondes, UASs, and oceanographic profilers (OP)). When UAS 

weather instruments are released or activated within a WRA: (a) only a single participating 

aircraft conducting the UAS weather instrument release is permitted to operate within the WRA, 

and (b) the aircraft commander is responsible for ensuring no other participating aircraft are 

operating in the WRA.

6.2.4. Buoy Deployment Mission

Regardless of the designated class of airspace (A through G) the following rules apply:

6.2.4.1. Flight Plan. A normal IFR flight plan will be filed for this mission. The coordinates 

for some of the planned deployments may need to be changed while en route to adjust to the 

forecast track of the storm. CARCAH will be responsible for relaying any revisions to the flight 

crew. The aircraft routing will not be altered by ATC because the buoys must exit the aircraft in 

a specified order and they cannot be rearranged in flight.

6.2.4.2. Procedures. It is preferred that these missions be filed and flown using IFR 

procedures in either controlled or uncontrolled airspace. However, with the concurrence of the 

aircraft commander, they may be flown VFR. If this change is made en route, ATC flight 

following and traffic advisories will be requested by the aircrew, and any changes to the route of 

flight must be relayed to ATC by the aircrew.

6.2.5. High Altitude Synoptic Track Missions.

6.2.5.1. Flight Plan. A normal IFR flight plan will be filed for this mission.

6.2.5.2. NOTAM. A NOTAM request must be submitted by the 53 WRS, NOAA AOC, NASA, 

NSF, or NRL for any High Altitude Synoptic Track mission that will release weather instruments 

(e.g., dropsondes, etc). The NOTAM must contain individual coordinates or an area defined by 

coordinates for all releases. Submit NOTAM request per Appendix D procedures.

6.2.5.3. Release of Dropsondes. During NHOP missions and when operationally feasible, 

dropsonde instrument releases from FL 190 or higher and sensor activation must be coordinated 
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with the appropriate en route ATC facility by advising of a pending drop or sensor activation 

about 10 minutes prior to the event when in direct radio contact with ATC. When ATC has radar 

contact with the aircraft, they will notify the aircrew of any known traffic below them that might 

be affected. The aircraft commander is solely responsible for release of the instrument after 

clearing the area by all means available.

• When contact with ATC is via ARINC, event coordination must be included with the 

position report prior to the point where the action will take place, unless all instrument 

release points have been previously relayed to the affected ATC facilities. Contact between 

participating aircraft must be made using the frequencies listed in the second bullet of 

paragraph 6.2.1.8.

• During NHOP missions, approximately five (5) minutes prior to release the aircrew will 

broadcast in the blind on radio frequencies 121.5 MHz and 243.0 MHz to advise any traffic 

in the area of the impending drop. Pilots must not make these broadcasts if they will interfere 

with routine ATC communications within the vicinity of an ATC facility. The aircraft 

commander is responsible for determining the content and duration of a broadcast, 

concerning the release or sensor activation.
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CHAPTER 7: SATELLITE SURVEILLANCE OF 

TROPICAL AND SUBTROPICAL CYCLONES

7.1. Satellites.

7.1.1. Geostationary Operational Environmental Satellite (GOES).

Using modern 3-axis stabilization for orbit control, GOES-13 (GOES-East) at 75°W and GOES15 (GOES-West) at 135°W support the operational two-GOES constellation. Independent imager 

and sounder instruments eliminate the need to timeshare, yielding an increase in spatial coverage 

of image and sounder data at more frequent scanning intervals. However, the GOES-13 sounder 

failed in November 2015 and no sounder data has been available from it since that time. The 

GOES also provides higher resolution and additional spectral channels than its predecessor, 

affording the hydrometeorological community improvements in detection, monitoring, and 

analysis of developing tropical cyclones. From 135°W and 75°W, routine GOES satellite data 

coverage is extensive, stretching from the central Pacific through the Americas to the eastern 

Atlantic, including the vital breeding grounds for tropical cyclones.

Routinely, each GOES schedule provides two views of the CONUS (GOES-West view is termed 

PACUS) every 15 minutes. More frequent interval scans can be employed to support NOAA's 

warning programs, including the tracking of tropical and subtropical cyclones. Government 

agencies and the private sector have access to digital data transmissions directly from 

NOAAPORT, from NOAA’s Environmental Satellite Processing Center (ESPC), or directly 

from GOES.

The current series of GOES satellites provide satellite data generated from full resolution imager 

and sounder data. Imagery at 1 and 4 km resolution is available for daytime and nighttime 

applications. Visible data are available at 1 km, “shortwave” infrared (channel 2 data) as well as 

the infrared channels 3, 4, and 5 are available at 4 km resolution. Water vapor (channel 3) is 

available at 4 km resolution on GOES East and West. Channel 2 (Shortwave IR) data are 

valuable for the detection of low clouds, fog, stratus, and surface hot spots. On GOES East, 

channel 6 is a 13.3 μm band that is useful in the detection of CO2. Channel 6 improves the 

measurement of the height of clouds, derived winds and volcanic ash, thus improving computer 

model forecasts and ash warnings to the aviation community. The digital data may be enhanced 

to emphasize different features as desired. A suite of digital data and environmental products is 

available to users in the National Weather Service (NWS); the National Environmental Satellite, 

Data, and Information Service (NESDIS); other Federal agencies; the academic community; and 

many private agencies, both national and international. These data are made available through 

NOAAPORT, from ESPC, the Internet, and other means such as local networks.

7.1.1.1. GOES East. GOES-East is stationed at 75°W and serves NOAA operations, to include 

the NHC, other Federal agencies, and the private sector. Various imager channels at higher 

resolutions are being utilized to monitor the intensification and movement of tropical cyclones 

over the Atlantic Ocean and a portion of the East Pacific. In particular, greater detail in the 

imagery facilitates tropical cyclone monitoring and analysis, and the use of the GOES imager 

channel 2 has vastly improved the detection of low-level circulation centers at night to assist in 

storm positioning. Retrievals from the GOES sounder are being incorporated into NCEP's 
7-2

numerical models to improve model output. In addition, sounder data are being exploited to 

generate derived product imagery such as total precipitable water, atmospheric stability indices, 

surface temperatures and cloud heights.

7.1.1.2. GOES West. GOES West is stationed at 135°W. The routine scanning mode of 

GOES-West provides coverage of the Northern and Southern Hemisphere eastern Pacific Ocean 

as well as the western United States. The GOES-West satellite also supports the missions of both 

the NHC and the CPHC, and provides coverage of developing tropical cyclones over the East 

and Central Pacific. The DOD and other Federal agencies are also supported.

During the 2008 Central Pacific hurricane season, NESDIS instituted a specialized GOES-West 

sounder schedule consisting of additional Hawaii sectors. During routine operation, the GOESWest sounder scans two Hawaii and four North Pacific sectors. To aid in the surveillance and 

input of additional sounder data into hurricane models, the Central Pacific Hurricane Center 

(CPHC) can request an alternate GOES-West sounder schedule that replaces two North Pacific 

sectors with two Hawaii sectors, allowing for four Hawaii sector scans and two North Pacific 

sector scans in a six-hour period.

7.1.1.3. GOES-N Series.The GOES-N Series will be used to continue and enhance the 

environmental monitoring and communications functions of the GOES-I thru M (GOES-8 thru 

12) series of NOAA operational spacecraft. GOES-13, the first in the GOES-N series, was 

designed with a different spacecraft bus than the previous GOES series, and contains larger 

power cells. This design results in the increased accuracy in navigation and instrument 

radiometrics, and the operation of the imager and sounder through the satellite “eclipse” season. 

GOES-O and GOES-P were also procured as part of the GOES-N series contract. GOES-O was 

launched on June 27, 2009 and renamed GOES-14; GOES-P was launched on March 4, 2010 

and was renamed GOES-15.

7.1.1.4. GOES-13.GOES-13 was launched on May 24, 2006. GOES-13 is the first of the 

GOES N series of satellites and is currently the operational GOES-East satellite.

7.1.1.5 GOES-14. GOES-14 was launched on June 27, 2009. It is currently positioned at 105W

and is in backup storage mode.

7.1.1.6. GOES-15. GOES-15 was launched on March 4, 2010. GOES-15 is the last of the 

GOES N series of satellites and is currently the operational GOES-West satellite.

7.1.1.7. GOES-16. GOES-16 launched on November 19, 2016. GOES-16 is the first of the 

GOES-R series of satellites and is currently in the post-launch testing phase to prepare it for 

operations later in 2017. The post-launch test phase is expected to complete in June 2017, at 

which time the satellite will be handed over to the NOAA Office of Satellite and Product 

Operations. After that time, GOES-16 will undergo an additional six months of extended 

validation before moving to its final location in November 2017, when GOES-16 data will be 

deemed operational.

The capabilities of GOES-16 and subsequent satellites to be launched in this series are much 

greater than with the current GOES satellites. Routine imaging over the CONUS will occur at 5 

minute frequency with Full Disk coverage every 15 minutes. There is also the capability for 

mesoscale sector coverage, which could include tropical storms, as frequently as every 30 
7-3

seconds. There are 16 spectral bands on the imager - 2 in the visible spectrum and 14 in the 

Infrared/Near-Infrared. Band 2 (0.64 μm in the red visible wavelength) has a nominal resolution 

of .5 km while band 1 (0.47 μm in the blue visible wavelength) has a resolution of 1 km. Two of 

the Near-IR bands (band 3 at .86 μm and band 5 at 1.6 μm) have 1 km resolution. All other 

Near-IR and IR bands are at 2 km resolution. In addition to the individual channel imagery a 

number of multispectral derived products for a wide variety of applications will also be 

available. This series of satellites does not have a sounder instrument. The Geostationary 

Lightning Mapper (GLM) instrument aboard GOES-16 detects total lightning activity across the 

Western Hemisphere: in cloud, cloud-to-cloud, and cloud-to-ground.

Note: GOES-16 has not been declared operational and its data are preliminary and undergoing 

testing. Users receiving these data through any dissemination means (including, but not limited 

to, Product Distribution and Access [PDA] and GOES-R Rebroadcast [GRB]) assume all risk 

related to their use of GOES-16 data and NOAA disclaims and any and all warranties, whether 

express or implied, including (without limitation) any implied warranties of merchantability or 

fitness for a particular purpose.

7.1.2. EUMETSAT Meteosat Geostationary Satellites.

Meteosat-10, launched in July 2013, became EUMETSAT’s Prime 0 degree satellite in January 

2013, replacing Meteosat-9. It provides vital coverage of developing tropical waves off the 

African Coast and eastern Atlantic Ocean. As one of the Meteosat Second Generation (MSG) 

satellites, Meteosat-10 has a 12 channel Spinning Enhanced Visible and InfraRed Imager 

(SEVIRI) instrument to sense the earth’s environment across a broad spectral frequency 

spectrum. Conventionally, the full disk IR, visible (VIS), and water vapor imagery have a 3 km 

resolution whereas a specialized VIS sector provides a maximum 1 km resolution. This 

specialized high resolution visible (HRV) sector has a limited scan area, and will shift from the 

West Indian Ocean to the East Atlantic Ocean during daylight/visible hours every day during the 

summer hurricane season. This shift will ensure operational interests monitoring for tropical 

activity in the North Indian Ocean (Meteo-France) as well as the East Atlantic (NHC) will be 

satisfied.. The digital full disk encrypted data are downlinked from a DOMestic SATellite 

(DOMSAT) at NSOF/ESPC, Suitland, MD, every 15 minutes and are then transmitted 

unencrypted to NESDIS and NCEP at the NOAA Center for Weather and Climate Prediction 

(NCWCP) in College Park, MD. The unencrypted Meteosat-10 data are also made available to 

the NWS NHC and the NWS Storm Prediction Center (SPC). In February 2017, Meteosat-8

replaced Meteosat-7 as the prime mission for the Indian Ocean Data Coverage. Stationed at 

41.5E, Meteosat-8 provides essential coverage to monitor tropical cyclone formation and 

development over the Indian Ocean. The Meteosat-8 data policy is the same as used for 

Meteosat-10. 

In December 1995, EUMETSAT, the program administrator, began encrypting digital Meteosat 

data 24 hours per day to regulate use for non-members in Europe, Asia, and Africa. Based on 

international data policy agreements, U.S. non-government users are allowed access via the 

DOMSAT and NESDIS/NSOF/ESPC to non-encrypted digital Meteosat data 8 times per day at 

synoptic times; at other times, the data are encrypted. Hence, if quarter-hourly transmissions are 

required to support operational requirements, it is necessary for users to register with 

EUMETSAT to obtain a user agreement for installation of a Meteosat receive station at their 
7-4

local site (NOAA and DOD and other U.S. government agencies are registered with 

EUMETSAT).

7.1.3. COMS-1.

The Communication, Ocean and Meteorology Satellite (COMS) is the first operational weather 

and ocean satellite from The Republic of Korea. COMS-1 was developed by the Korean 

Astronomical Research Institute (KARI) through contract with EADS Astrium, and carries a 5 

channel imager similar to the imager on board GOES L-N. Full disk images are directly 

broadcast from the satellite every 27 minutes. Stationed at 128E, the Korean Meteorological 

Administration (KMA) began prime operations of COMS-1 in 2011, providing supplemental 

coverage of the West Pacific and East Indian oceans. The primary U.S government user of 

COMS-1 data is DoD.

7.1.4. Initial Joint Polar System (IJPS). 

Two primary operational polar orbiting satellites, NOAA’s NOAA-19 and EUMETSAT’s 

Metop-A, provide image coverage four times a day over a respective area in 6 spectral channels 

(however only 5 channels can be supported at one time; channel switching is used to support the 

6th channel). These satellites cross the U.S. twice per day at 12-hour intervals for each 

geographical area near the Equatorial crossing times listed in Table 7-2. NOAA-19 and Metop-A 

provide the same capabilities as previous NOAA satellites, except that the Advanced Microwave 

Sounding Unit–B (AMSU-B) sensor flown aboard NOAA-17 and previous polar orbiters has 

been replaced by the Microwave Humidity Sounder (MHS) on NOAA-19. Data are available via 

direct readout—high-resolution picture transmission (HRPT) or automatic picture transmission 

(APT)—or via central processing. Data from the Advanced Very High Resolution Radiometer 

(AVHRR) on NOAA-19 and the corresponding Visible Infrared Imaging Radiometer (VIIRS) on 

board Metop-A are available on a limited basis through the GOES distribution system (Figure 7-

1). The Air Force 557th Weather Wing (557 WW), Offutt AFB, NE, receives global data from 

the Advanced Scatterometer (ASCAT) on board Metop-A direct from central readout sites on a 

pass-by-pass basis. The Command and Data Acquisition (CDA) stations at Fairbanks, AK, and 

Wallops, VA, acquire recorded global area coverage data sub-sampled to a 4 km spatial 

resolution, and then route the data to NESDIS computer facilities in Suitland, MD, where the 

data are processed and distributed to the NOAA, the DOD, and private communities. Ground

equipment installed at various NWS regions including Kansas City, Miami (NHC), and 

Monterey enable direct readout and data processing of 1.1 km resolution AVHRR and VIIRS 

data from NOAA-19 and Metop-A. The high resolution polar data and products generated at 

NHC complement other satellite data sources to support tropical mission objectives.

7.1.5. Non-NOAA Satellites. 

NOAA uses dedicated ground support systems to ingest and process data from select NonNOAA satellite systems for use in operational forecasting and tropical cyclone analysis. These 

include data from the NASA Earth Observing System (EOS) satellites: Terra, Aqua, and Aura; 

CORIOLIS from the Department of Defense; Jason-2 and Jason-3 from the joint NOAA, NASA, 

Centre National d’Etudes Spatiales (CNES), and EUMETSAT mission; and SARAL from the 

cooperative altimetry technology mission of the Indian Space Research Organisation and CNES. 

These satellites employ multiple infrared and microwave radiometers as well as active 
7-5

scatterometers to assess environmental features on the ocean surface. NOAA considers these 

datasets non-operational, and obtains the data on a best effort basis.

7.1.5.1. Jason-2 and Jason-3. Jason-2 and its follow-on mission Jason-3 are joint NOAA, 

NASA, CNES, and EUMETSAT satellites launched on June 20, 2008 and January 17, 2016, 

respectively. Jason-2 is in an interleaved orbit with Jason-3 providing maximum global spatial 

coverage. The Jason missions are designed to study ocean surface topography and provide near 

real-time sea surface height, ocean surface wind speed, and significant wave height 

measurements. Jason-2 and Jason-3 each utilize a two-frequency Poseidon radar altimeter 

operating at 13.575 GHz (Ku-band) and 5.3 GHz (C-band) and an Advanced Microwave 

Radiometer consisting of three separate channels at 18.7, 23.8 and 34 GHz. The 23.8 GHz 

channel is the primary water vapor sensing channel, meaning higher water vapor concentrations 

lead to larger 23.8 GHz brightness temperature values. The addition of the 34 GHz channel and 

the 18.7 GHz channel, which have less sensitivity to water vapor, facilitate the removal of the 

contributions from cloud liquid water and excess surface emissivity of the ocean surface due to 

wind, which also act to increase the 23.8 GHz brightness temperature. The sea-surface height 

measurements are made with a globally averaged RMS accuracy of 3.4 cm (1 sigma), or better, 

assuming 1 second averages.

7.1.5.2. Oceansat-2. Oceansat-2 is an Indian satellite, launched September 23, 2009, by the 

Indian Space Research Organisation (ISRO). Oceansat-2 is designed to study surface winds and 

ocean surface strata as well as other oceanic and atmospheric properties. Oceansat-2 is currently 

completing calibration and validation phase for certification. Oceansat-2 carries two payloads for 

ocean related studies, Ocean Colour Monitor (OCM) and Ku-band pencil-beam Scanning 

Scatterometer (SCAT). SCAT will be used to determine ocean surface level wind vectors 

through estimation of radar backscatter. SCAT will provide valuable ocean surface wind vector 

data for monitoring tropical cyclone formation and development, especially since the loss of 

QuikScat on November 23, 2009.

7.1.5.3 Himawari-8. Himawari-8 is a Japanese satellite, the 8th of the Himawari geostationary 

weather satellites operated by the Japan Meteorological Agency. Himawari-8, launched in 

October 2014, replaced MTSAT-2 as JMA’s prime geostationary satellite at 140E in July 2015.

At 140E, the satellite provides vital coverage of the West Pacific to monitor the development of 

tropical cyclones, many of which transition to typhoon intensity. At a spatial resolution and 

number of channels equal to NOAA GOES-16 ABI, the Himawari-8 Advanced Himawari 

Imager (AHI) consists of 16 spectral channels transmitted in full disk images every 10 minutes.

The higher spatial resolution and higher number of channels from the AHI provide significant 

improvements in monitoring, intensity, and forecasting of tropical cyclones over the West Pacific 

Ocean. Through an agreement, NOAA acquires Himawari-8 data from JMA’s Himawari Cloud 

service and then makes the data available to many NOAA sites including NESDIS SAB and 

NWS NCO and DoD.

7.1.5.4 GPM The Global Precipitation Measurement (GPM) mission is an international network 

of satellites that provide the next-generation global observations of rain and snow. The GPM 

core Observatory, initiated by NASA and the Japan Aerospace Exploration Agency (JAXA) as a 

global successor to TRMM, serves as a reference standard to unify precipitation measurements 

from the GPM constellation of research and operational satellites. The GPM Core Observatory 

was launched on February 27th, 2014 at 1:37pm EST from Tanegashima Space Center. The 
7-6

onboard instrument, GPM microwave imager (GMI) measures microwave radiance at seven 

frequencies(10.65GHz, 18.70GHz, 23.80GHz, 36.50GHz, 89.0GHz), which are subsequently 

processed and converted into different GPM data and products. NOAA/NESDIS has integrated 

the GPM GMI data into a few operational applications whose products are used by National 

Hurricane Center, including Microwave Integrate Retrieval System (MiRS), Blended Total 

Precipitable Water (bTPW), Ensemble Tropical Rainfall Potential (eTRaP). NESDIS also 

reformats the GPM data, specifically the L1C-R data, into the Binary Universal Format (BUFR) 

for use by the NOAA NWP community, and some international agencies. 

7.1.6 JPSS Satellites.

7.1.6.1 S-NPP.Suomi National Polar-Orbiting Partnership satellite (SNPP) launched in 

October, 2011, is part of the Joint Polar Satellite System (JPSS), the next generation polarorbiting operational environmental satellite system. SNPP carries five instruments, including 

Visible Infrared Imaging Radiometer Suite (VIIRS) and Advanced Technology Microwave 

Sounder (ATMS). The time scale of tropical cyclone track and intensity changes is on the order

of 12 hours, which makes JPSS instruments well suited for the forecasting of these parameters. 

Two basic methods exist for improving tropical cyclone forecasts with SNPP. First is to 

assimilate data in numerical forecast models, and second is to improve analysis and statistical 

post-processing forecast products. NOAA/NESDIS has integrated the S-NPP data into a few 

operational applications whose products are used by National Hurricane Center, including MiRS, 

bTPW, and eTRaP. NESDIS also reformats the S-NPP ATMS data into the BUFR for use by the 

NOAA NWP community, and some international agencies. 

7.1.6.2 GCOM-W1. The "Global Change Observation Mission" (GCOM) is a series of JAXA 

Earth missions lasting 10-15 years designed to obtain observations related to water and climate. 

The GCOM-W1 was launched May 18, 2012 and is the first satellite of the GCOM-W series.

GCOM-W1 is in a sun-synchronous orbit (~700 km altitude) and part of the “A-Train” with an 

ascending node equator crossing time of 13:30 UTC. The AMSR2 (Advanced Microwave 

Scanning Radiometer 2) instrument onboard the GCOM-W1 satellite will continue Aqua/AMSRE observations of water vapor, cloud liquid water, precipitation, SST, sea surface wind speed, 

sea ice concentration, snow depth, and soil moisture. NOAA/NESDIS has integrated the GCOMW1 data into a few operational applications whose products are used by National Hurricane 

Center, including bTPW, eTRaP, GCOM-W1 AMSR2 Algorithm Software Package (GAASP). 

NESDIS also reformats the GCOM-W1 AMSR2 data into the BUFR for use by the NOAA NWP 

community, and some international agencies. 

7.2. National Weather Service (NWS) Support.

7.2.1. Station Contacts. 

The GOES imagery is available in support of the surveillance of tropical and subtropical 

cyclones at specific NWS offices. Satellite meteorologists can be contacted at these offices; 

telephone numbers are in Appendix I.

7.2.2. Products. 

Satellite-related products are listed in Chapter 3, Table 3-5, “Summary of Products and their 

Associated WMO Header.”
7-7

7.2.2.1. Tropical Weather Discussions. NHC issues these discussions four times a day 

based on satellite imagery, meteorological analysis, weather observations and radar. They 

describe significant features and significant weather areas for the Gulf of Mexico, the Caribbean, 

and between the equator and 32°N in both the Atlantic and eastern Pacific east of 140°W.

7.2.2.2. Satellite Interpretation Messages. WFO Guam issues these discussions two times 

a day to describe synoptic features and significant weather over the Micronesian waters.

7.3 NESDIS Satellite Analysis Branch (SAB). 

The SAB operates 24 hours a day to provide satellite support to the WPC/OPC, NHC, CPHC, 

JTWC, and other worldwide users. In addition to providing high quality imagery from 

geostationary and polar-orbiting satellites and coordinating the execution of non-operational 

GOES Rapid Scan Operations (RSO) requests, SAB provides pertinent information on global 

tropical cyclone development, including location and intensity analysis based on the Dvorak 

technique (Table 7-1). Estimates of cumulative rainfall expected over coastal areas derived using 

the eTRaP methodology are provided for tropical cyclones and posted to a web site in support of 

CPHC, WPC, NHC, forecast offices in U.S. territories, and international customers. Telephone 

numbers for the SAB are located in Appendix I.
7-8

Table 7-1. Communications Headings for SAB Dvorak Analysis Products

WMO HEADING OCEANIC AREA TYPE OF DATA

TXST20-21 KNES South Atlantic Ocean VIS/IR

TXNT Atlantic VIS/IR

TXPN Central Pacific VIS/IR

TXPQ West Pacific VIS/IR

TXPS South Pacific VIS/IR

TXPZ East Pacific VIS/IR

TXIO North Indian VIS/IR

TXXS South Indian VIS/IR

7.4. Air Force Support and the Defense Meteorological Satellite 

Program (DMSP).

Data covering the National Hurricane Operations Plan areas of interest are received centrally at 

the Air Force 557th Weather Wing (557 WW) and distributed to the Air Force’s Operational 

Weather Squadrons (OWS) and the Navy’s Fleet Numerical Meteorology and Oceanography 

Center (FNMOC) at Monterey, CA. Satellite data covering the Central Pacific area are received 

at or shipped to the 17th OWS Meteorological Satellite Operations (SATOPS) Flight (17 

OWS/WXJ), Joint Typhoon Warning Center, Pearl Harbor, HI. The 17 OWS/WXJ uses all 

available meteorological satellite data when providing fix and or intensity information to Central 

Pacific Hurricane Center forecasters. 

7.4.1. Central Pacific Surveillance. The 17 OWS/WXJ (JTWC Satellite Operations) will 

provide, resources permitting, fix and intensity information to the CPHC on systems upon 

request.

7.5. Satellites and Satellite Data Availability for the Current Hurricane 

Season. 

Table 7-2 lists satellite capabilities for the current hurricane season.

7.6. Current Intensity and Tropical Classification Number Using the 

Dvorak Technique. 

The current intensity (C.I.) number relates directly to the intensity of the storm. The empirical 

relationship between the C.I. number and a storm's wind speed is shown in Table 7-3. The C.I. 

number is the same as the tropical classification number (T-number) during the development 

stages of a tropical cyclone but is held higher than the T-number while a cyclone is weakening. 

This is done because a lag is often observed between the time a storm pattern indicates 

weakening has begun and the time when the storm's intensity decreases. An added benefit of this 

rule is the stability it adds to the analysis when short-period fluctuations in the cloud pattern 

occur. 
7-9

Table 7-2. Satellite and Satellite Data Availability for the Current Hurricane Season

SATELLITE TYPE OF DATA SCAN TIME PRODUCTS

GOES-13

GOES-15 

Multispectral 

Imager and 

Sounder; 5 Channels 

for Imager; 19 

Channels for 

Sounder 

GOES East and GOES West: 

Every 30 min, in Routine Scan 

Mode, provides 3 sectors with 

prescribed coverages: 

Northern Hemisphere (NH) or 

Extended NH; CONUS or 

PACUS; and Southern 

Hemisphere. Exception is 

transmission of full disk every 

3 hours. (Available Rapid 

Scan Operations yield 

increased transmissions to 7.5 

minute intervals to capture 

rapidly changing, dynamic 

weather events).

1. 1, 2, 4, and 8 km resolution visible 

standard sectors.

2. 4 km equivalent resolution IR 

sectors.

3. Equivalent and full resolution IR 

enhanced imagery.

4. Full disk IR every 3 hours.

5. 4 km water vapor sectors

6. Quantitative precipitation estimates; 

high density cloud and water vapor 

motion wind vectors; and 

experimental visible and sounder 

winds.

7. Operational moisture sounder data 

(precipitable water) in four levels for 

inclusion in NCEP numerical models. 

Other sounder products including 

gradient winds, vertical temperature 

and moisture profiles, mid-level 

winds, and derived product imagery 

(precipitable water, lifted index, and 

surface skin temperature). 

8. Tropical storm monitoring and 

derivation of intensity analysis. 

9. Volcanic ash monitoring and 

dissemination of Volcanic Ash 

Advisory Statements.

10. Daily northern hemisphere snow 

cover analysis.

11. Twice daily fire and smoke 

analysis over specific areas within 

CONUS.

GOES-16 Multi-band imager 

(16 spectral 

channels)

Full disk every 15 minutes

CONUS 5 minute frequency

Mesoscale Sector coverage 

every 30 seconds

1. ABI band 2 is .5 km resolution

2. Bands 1, 3, 5 are 1 km resolution 

and all other banks are 2 km 

resolution. 

3. GLM provides total lightning 

activity across the Western 

Hemisphere.

4. For list of baseline products see: 

http://www.goesr.gov/products/baseline.html

(Note: GOES-16 L2+ products are not 

yet available.)
7-10

Table 7-2. Satellite and Satellite Data Availability for the Current Hurricane Season

SATELLITE TYPE OF DATA SCAN TIME PRODUCTS

METEOSAT-10 

at 0° (Prime 

Meridian)

METEOSAT-8 

at 41.5°E (Indian 

Ocean)

Multi-spectral

Spin-Scan

Radiometer 

(SEVIRI) and High 

Resolution Visible 

(HRV)

SEVIRI: Full disk image 

every 15 minutes.

HRV: Sector scan to move 

with local noon/available 

daylight.

1. 1 km resolution VIS imagery 

(HRV); 3 km resolution IR imagery 

(SEVIRI).

2. 3 km resolution VIS and IR 

WEFAX imagery.

3. 3 km water vapor imagery.

4. Tropical storm monitoring and 

intensity analysis.

5. Volcanic ash detection and analysis.

Himawari-8 at 

140°E (Asian 

Pacific)

Multi-band imager 

(16 spectral 

channels)

Full disk every 10 minutes 1. AHI .5 km band 3 resolution 

2. 1 km resolution for bands 1, 2, and 

4. All other bands 2 km resolution.

3. Tropical storm monitoring and 

intensity analysis.

4. Volcanic ash detection and analysis

5. Aerosol monitoring.

COMS-1 at 

128°E (Asian 

Pacific)

Meteorological 

Imager (MI) (5 

spectral channels)

Full disk every 30 minutes 1.MI 1 km resolution VIS imagery.

2. MI 4 km resolution in 4 IR 

channels.

3. Tropical storm monitoring.

4. Aerosol monitoring.

GPM (Global 

Precipitation 

Mission)

GMI Fluctuates from 60°N to 60°S 1. Microwave Integrate Retrieval 

System (MiRS)

2. Blended Total Precipitable Water 

(bTPW)

3. Ensemble Tropical Rainfall 

Potential (eTRaP)

S-NPP VIIRS and ATMS Every 12 hours 1. Microwave Integrate Retrieval 

System (MiRS)

2. Blended Total Precipitable Water 

(bTPW)

3. Ensemble Tropical Rainfall 

Potential (eTRaP)

4. Cross-track Infrared Sounder (CrIS) 

to monitor moisture and pressure

GCOM-W1 AMSR2 Sun-synchronous orbit (~700 

km altitude) ascending node 

equator crossing time of 13:30 

UTC

1. Blended Total Precipitable Water 

(bTPW)

2. Ensemble Tropical Rainfall 

Potential (eTRaP)

3. GCOM-W1 AMSR2 Algorithm 

Software Package (GAASP)
7-11

Table 7-2. Satellite and Satellite Data Availability for the Current Hurricane Season

SATELLITE TYPE OF DATA SCAN TIME PRODUCTS

MetOp-A

NOAA-19

NOAA-18 

secondary

NOAA-15 

secondary

AVHRR; GAC and 

LAC (recorded); 

HRPT (direct); 

AMSU-A; AMSU-B 

(N-17); MHS (N19); HIRS VIIRS 1 

km global

Local Crossing Times:

0931D1

/2131A2

0156D/1343A

1. 1 km resolution HRPT and Local 

Area Coverage (LAC) data. 

2. 4 km resolution APT and Global 

Area Coverage (GAC) data.

3. Mapped imagery.

4. Unmapped imagery (all data types) 

at DMSP sites.

5. Sea-surface temperature analysis.

6. Soundings.

7. Moisture profiles.

8. Remapped GAC sectors.

9. Sounding-derived products--total 

precipitable water, rain rate, and 

surface winds under sounding 

10. Daily northern hemisphere snow 

cover analysis.

11. Twice daily fire and smoke 

analysis over specific areas within 

CONUS.

12. AMSU based tropical cyclone 

intensity estimates.

DMSP F-14 

Tactical

DMSP F-15 

Secondary 

DMSP F-16 

Secondary

DMSP F-17 Ops

DMSP F-18 Ops

OLS Imagery 

(recorded and 

direct), SSM/I, 

SSM/T-1 (inop), 

SSM/T-2

OLS Imagery 

(recorded and 

direct), SSM/I, 

SSM/T-1, SSM/T-2

OLS Imagery 

(recorded and 

direct), SSM/IS

OLS Imagery 

(recorded and 

direct), SSM/IS

OLS Imagery 

(recorded and 

direct), SSM/IS

0424D/1557A

0841D/2041A

0732D/1905A

0528D/1728A

0801D/2001A

Note: Times are accurate to ± 

5 minutes

1. 0.3 nm (regional) and 1.5 nm 

(global) resolution (visual and 

infrared) imagery available via stored 

data recovery through 557 WW.

2. Regional coverage at 0.3 nm and 

1.5 nm resolution (visual and infrared) 

imagery available from numerous 

DOD tactical terminals.

3. SSM/T-1, SSM/T-2, SSM/I, and 

SSM/IS data transmitted to NESDIS 

and FNMOC from 557 WW.

1 D - descending

2 A - ascending
7-12

Table 7-3. The Dvorak Technique: The Empirical Relationship* between the C.I. Number 

and the Maximum Wind Speed and the Relationship between the T-Number and the 

Minimum Sea-Level Pressure (SLP) 

C.I. NUMBER MAXIMUM 

WIND SPEED T-NUMBER MINIMUM SLP (Atlantic)

MINIMUM SLP 

(NW Pacific)

1 25 kt 1

1.5 25 1.5

2 30 2 1009 mb 1000 mb

2.5 35 2.5 1005 997

3 45 3 1000 991

3.5 55 3.5 994 984

4 65 4 987 976

4.5 77 4.5 979 966

5 90 5 970 954

5.5 102 5.5 960 941

6 115 6 948 927

6.5 127 6.5 935 914

7 140 7 921 898

7.5 155 7.5 906 879

8 170 8 890 858

*Dvorak, V, 1984: Tropical Cyclone Intensity Analysis Using Satellite Data. NOAA Tech Report NESDIS 11, Washington., 

D.C.
8-1

CHAPTER 8: SURFACE RADAR REPORTING

8.1. General.

Radar observations of tropical cyclones will be made at Department of Defense (DOD), National 

Weather Service (NWS), and Federal Aviation Administration (FAA) Weather Surveillance 

Radar-1988 Doppler (WSR-88D) facilities. Participating radar sites are listed in Table 8-1.

8.2. The WSR-88D.

The WSR-88D is a computerized radar data collection and processing system. The design and 

implementation of the WSR-88D was a joint effort of the DOD, NWS, and FAA, and the 

utilization of the radar continues to be governed by tri-agency agreement. The WSR-88D is an Sband (10-cm), coherent radar, with a nominal beam width of 1 degree. The maximum data ranges 

are 248 nm (reflectivity) and 124 nm (velocity), although velocity data out to 162 nm can be 

obtained from radars using “super-resolution.” Radar scanning strategies are selectable, using 

predetermined volume coverage patterns (VCPs). The VCP in use depends upon which weather 

phenomena are under surveillance. Once the radar data has been collected, it is processed 

automatically at the radar site by a suite of algorithms which provide graphical products for 

forecaster use. NHC, as an external user, obtains these products through a network connection.

CPHC obtains products directly from four WSR-88Ds in Hawaii operated by the NWS Weather 

Forecast Office in Honolulu.

8.3. Procedures.

As a tropical cyclone approaches, NHC uses the WSR-88D to perform radar center-fixing and to 

obtain other diagnostic information. Therefore, it is important to optimize WSR-88D 

performance for tropical cyclones and to allow other users, especially the NHC, access to radar 

products in the area of landfall. Most of the changes must be issued through the Master System 

Control Function (MSCF), Radar Product Generator (RPG) Human Computer Interface (HCI).

To facilitate this process, NHC in cooperation with the Radar Operations Center (ROC) has 

developed an operations plan for use during tropical cyclone events. The current WSR-88D

Tropical Cyclone Operations Plan is available as a sub-link to the National Hurricane Operations 

Plan on the OFCM web site at http://www.ofcm.gov/publications/nhop/nhop2.htm. It is also 

available via fax from the ROC Hotline (1-800-643-3363).

8.3.1. Radar Observation Requirements, WSR-88D. 

Chief among the requirements is the appropriate display of hurricane-force winds. Changes must 

be made at the radar site, guided by the WSR-88D Tropical Cyclone Operations Plan, in order to 

deal effectively with hurricane conditions. The physical characteristics of the tropical cyclone are 

best represented by use of the precipitation mode. Choice of VCP may significantly enhance (or 

degrade) collection of velocity data (see WSR-88D Tropical Cyclone Operations Plan for further 

information). Further discussion of product usage appears in Section 4.11 of FMH-11, Part D, 

Unit Description and Operational Applications. A recommended WSR-88D product list 

associated with tropical cyclones appears in Table 4-3 of FMH-11, Part D.
8-2

Table 8-1. Participating WSR-88D Radar Stations1

NWS Radars

U.S. Gulf and Atlantic Coasts

NWS Radars

U.S. Southwest

FAA

Radars

DOD Radars

Albany, NY

Atlanta, GA

Binghamton, NY

Birmingham, AL

Boston, MA

Brandon/Jackson, MS

Brownsville, TX

Caribou, ME

Charleston, SC

Columbia, SC

Corpus Christi, TX

Ft. Worth, TX

Greer, SC

Houston, TX

Huntsville/Hytop, AL

Jacksonville, FL

Key West, FL

Lake Charles, LA

Melbourne, FL

Miami, FL

Mobile, AL

Morehead City, NC

New Orleans/Baton Rouge, LA

New York City, NY

Philadelphia, PA

Portland, ME

Raleigh/Durham, NC

Roanoke, VA

San Antonio, TX

Shreveport, LA

State College, PA

Sterling, VA

Tallahassee, FL

Tampa, FL

Wakefield, VA

Wilmington, NC

Los Angeles, CA

Phoenix, AZ

San Diego, CA

Santa Ana Mtns, CA

Tucson, AZ

Yuma, AZ

Molokai, HI

Kohala, HI

San Juan, PR

South Hawaii, HI

South Kauai, HI

Andersen AFB, Guam

Columbus AFB, MS

Dover AFB, DE

Eglin AFB, FL

Fort Hood, TX

Fort Polk, LA

Fort Rucker, AL

Maxwell AFB, AL

Moody AFB, GA

Robins AFB, GA

 

1

The criterion for selection is that the radar site is located within approximately 124 nm (legacy 

maximum velocity range) of the coastline.
8-3

8.3.2. Central Region Report.

The following fix definitions and criteria are used in reporting tropical cyclone radar 

observations:

• If the central region of a storm is defined by an identifiable circular, or nearly circular, wall 

cloud with an echo-free center, the fix (the geometric center) is reported as an "EYE".

• If the central region is recognizable, but not well-defined by a wall cloud (as in the case of a 

tropical storm), it is reported as a “CENTER."

• When the eye or center is only occasionally recognizable or some other central region 

uncertainty exists, the eye or center is reported as "PSBL EYE" or "PSBL CENTER."

• Remarks stating the degree of confidence will be included and will be classified as either 

"good," "fair," or "poor." If an eye is present, a "good" fix is reported when the eye is 

symmetrical--virtually surrounded by wall cloud; a "poor" fix is reported when the eye is 

asymmetrical--less than 50 percent surrounded by wall cloud; a "fair" fix is reported to 

express a degree of confidence between "good" and "poor." Note that a partial eyewall may 

be the result of excessive range from the radar, or represent the true structure of the system.

Doppler velocities will, in general, increase confidence in the center position and, if 

available, should always be examined prior to establishing a fix.

8.3.3. Transmission of Radar Reports. 

When the location of the center of a tropical cyclone can be reliably determined from radar data, 

and coastal tropical cyclone watches or warnings are in effect, the appropriate tropical cyclone 

warning center (NHC or CPHC) will issue a Tropical Cyclone Update (TCU) on an hourly basis 

in between Tropical Cyclone Public Advisory issuances.
8-4
9-1

CHAPTER 9: NATIONAL DATA BUOY CAPABILITIES 

AND REQUIREMENTS

9.1. General.

9.1.1. Automated Reporting Stations.

The National Data Buoy Center (NDBC) maintains automated reporting stations in the coastal 

and deep ocean areas of the Gulf of Mexico, the Atlantic and Pacific Oceans, and in the Great 

Lakes. These data acquisition systems collect real-time meteorological and oceanographic 

measurements for operational and research purposes. Moored buoys are deployed in the 

Southern Gulf of Mexico, the Caribbean and the Atlantic Ocean east of the Lesser Antilles for 

the primary purpose of supporting National Hurricane Center operations. NDBC also quality 

controls and releases meteorological data from the National Ocean Service Water Level 

Observing Network and from moorings and coastal stations operated by cooperating Regional 

Ocean Observing Systems. The NDBC website at http://www.ndbc.noaa.gov/ provides locations, 

latest operating status, and site-specific information for NDBC stations and provides links to 

details on partner organization stations. Specific questions may be addressed to NDBC Data 

Management and Communications Branch, Stennis Space Center, Mississippi 39529-6000, 

phone 228-688-2835.

9.1.2. Data Acquisition.

Moored buoy and Coastal-Marine Automated Network (C-MAN) stations routinely acquire, 

store, and transmit data every hour; a few selected stations report more frequently. Data obtained 

operationally include sea level pressure, wind speed and direction, peak wind, and air 

temperature. Sea surface temperature and wave spectra data are measured by all moored buoys 

and a limited number of C-MAN stations. Relative humidity is measured at several stations.

Ocean currents and salinity are measured at a few coastal stations.

NDBC acquires, encodes, and distributes data from partner organizations via NWS 

dissemination systems. Data from partner organizations pass through NDBC data quality control 

procedures prior to NWS dissemination. Frequency and timeliness of transmissions from these 

stations varies by organization.

9.1.3. Drifting Buoys.

9.1.3.1. NDBC. NDBC is capable of acquiring, preparing, and deploying drifting buoys; 

however, an operational drifting buoy requirement has not been identified or funded.

9.1.3.2. Navy. Since 1998, the Naval Oceanographic Office (NAVOCEANO) has deployed 

meteorological drifting buoys to report surface meteorological and oceanographic measurements, 

for operational purposes, as tropical systems move through data sparse regions tracking toward 

the U.S. East Coast. Additionally, Navy drifting buoys have been deployed in the Intertropical 

Convergence Zone (ITCZ). The drifting buoy measurements, which are available to tropical 

forecasters, provide invaluable input for defining tropical storm movement and intensity, 

improve forecast model initialization, and give tropical forecasters a much better sense of storm 

characteristics and track as they approach the fleet concentration areas of Jacksonville, FL, and 
9-2

Norfolk, VA. Drifting buoys typically have a life span of 1 to 2 years, and the data are available 

through the NAVOCEANO homepage and through standard World Meteorological Organization 

(WMO) data sources.

NAVOCEANO acquires, prepares, and deploys drifting meteorological buoys based on 

operational requirements identified by the Commander, U.S. Atlantic Fleet (COMLANTFLT).

Currently, COMLANTFLT has identified the Navy’s drifting buoy support as a standing 

requirement to support fleet safety, assist in fleet sortie decisions, and enhance tropical weather 

preparedness. 

9.2. Requests for Drifting Buoy Deployment.

Drifting buoy deployments should be coordinated through the Department of Commerce (DOC), 

National Oceanic and Atmospheric Administration (NOAA). Deployments will be requested 

through the Office of the Federal Coordinator for Meteorology (OFCM) to HQ Air Force 

Reserve Command (AFRC). Deployments in advance of a U.S. land-threatening hurricane 

require a 36- to 48-hour notification.

9.2.1. CARCAH.

CARCAH will issue, through the Tropical Cyclone Plan of the Day (TCPOD), an alert or 

outlook for drifting buoy deployment 48 hours before the planned deployment. Hard tasking for 

the deployment will be issued via the TCPOD at least 16 hours, plus flying time to the 

deployment location, before the event.

9.2.2. Deployment of Buoys.

DOC may request the deployment of a drifting buoy and subsurface float array with up to 40 

elements at a distance of 200 to 400 nm from the storm center, depending on the dynamics of the 

storm system. DOC will ensure the buoys and mission-related DOC personnel are delivered to 

AFRC. The specific DOC request for placement of the buoys will depend on several factors, 

including:

• Characteristics of the storm, including size, intensity, and velocity.

• Storm position relative to the coast and population centers.

• Availability of aircraft and Loadmasters (LM) certified for buoy deployment.

The Navy often works with the 53rd WRS to conduct ocean observations as part of regularly 

tasked tropical cyclone reconnaissance missions on a not-to-interfere basis, to include A-sized 

buoy deployments at transit altitudes.

9.2.3. Deployment Position.

The final deployment position will be provided before the flight crew briefing. An example of a 

possible buoy and float deployment pattern from the recent CLBAST Experiment is shown in 

Figure 9-1.

9.3. Communications.

Moored buoy and C-MAN data are transmitted via NOAA Geostationary Operational 
9-3

Environmental Satellite (GOES) to the National Environmental Satellite, Data, and Information 

Service (NESDIS) or via the Iridium satellite communication system and then are relayed to the 

NWS Telecommunications Gateway (NWSTG) for processing and dissemination. Data from 

partner organizations acquired by NDBC are relayed to the NWSTG for processing and 

dissemination. Moored buoy observations are formatted into the World Meteorological 

Organization (WMO) FM13 SHIP code. C-MAN and other partner organization coastal station 

data are formatted into C-MAN code, which is very similar to the WMO FM12 SYNOP code.

Drifting buoys transmit data via NOAA’s Polar Orbiting Environmental Satellites (POES) to the 

U.S. Argos Global Processing Center, Largo, Maryland. Service Argos processes and formats the 

data into WMO FM18 BUOY code. The messages are then routed to the NWSTG for 

distribution. The formats for WMO encoded messages may be found in the WMO Manual on 

Codes Volume One, WMO-No. 306.
9-4

Figure 9-1. Example Buoy and Float Deployment Pattern
10-1

CHAPTER 10: MARINE WEATHER BROADCASTS

10.1. General.

The National Weather Service and the Department of Homeland Security’s United States Coast 

Guard (USCG) broadcast forecast products that include information on tropical cyclones issued 

by the National Hurricane Center and the Central Pacific Hurricane Center. The broadcast of 

these products supports the U.S. participation in the Global Maritime Distress and Safety 

System, which provides the communications support to the International Maritime 

Organization's (IMO) global search and rescue plan. 

10.2. Global Maritime Distress and Safety System (GMDSS).

The goals of GMDSS are to provide more effective and efficient emergency and safety 

communications, and to disseminate maritime safety information to all ships on the world's 

oceans regardless of location or atmospheric conditions. These goals are defined in the 

International Convention for the Safety of Life at Sea (SOLAS) 1974, as amended. GMDSS is 

based upon a combination of satellite and terrestrial radio services and has changed international 

distress communications from being primarily ship-to-ship based to ship-to-shore (rescue 

coordination center) based. GMDSS provides for automatic distress alerting and locating, and 

requires ships to receive broadcasts of maritime safety information which could prevent a 

distress from happening in the first place. The NWS participates directly in the GMDSS by 

preparing weather forecasts and warnings for broadcast via two primary GMDSS systems--

NAVTEX and Inmarsat-C SafetyNET.

10.2.1. NAVTEX.

NAVTEX is an international, automated system for instantly distributing maritime navigational 

warnings, weather forecasts and warnings, search and rescue notices, and similar information to 

ships. It has been designated by the IMO as the primary means for transmitting coastal urgent 

marine safety information to ships worldwide. NAVTEX is broadcast from the 12 USCG 

stations. Coverage is reasonably continuous along the east, west, and Gulf coasts of the United 

States, as well as the area around Kodiak, Alaska, Guam, and Puerto Rico. Typical NAVTEX 

transmissions range from 200-400 nm.

10.2.2. SafetyNET.

Satellite systems operated by Inmarsat Ltd. are an important element of the GMDSS. Inmarsat-C 

provides ship/shore, shore/ship, and ship/ship store-and-forward data and telex messaging; the 

capability for sending preformatted messages to a rescue coordination center; and the SafetyNET 

service. The Inmarsat-C SafetyNET service is a satellite-based worldwide maritime safety 

information broadcast service of high seas weather warnings, navigational warnings, 

radionavigation warnings, ice reports and warnings generated by USCG-conducted International 

Ice Patrol, and other information not provided by NAVTEX.

10.3. Coastal Maritime Safety Broadcasts.

In addition to NAVTEX, the USCG and other government agencies broadcast maritime safety 
10-2

information, using a variety of different radio systems to ensure coverage of different ocean 

areas for which the United States has responsibility and to ensure all ships of every size and 

nationality can receive this vital safety information.

10.3.1. VHF Marine Radio.

The USCG broadcasts nearshore and storm warnings of interest to the mariner on VHF channel 

22A (157.1 MHZ) following an initial call on the distress, safety, and calling channel 16 (156.8 

MHZ). Broadcasts are made from over 200 sites, covering the coastal areas of the U.S., including 

the Great Lakes, major inland waterways, Puerto Rico, Alaska, Hawaii, and Guam. All ships in

U.S. waters over 20 meters in length are required to monitor VHF channel 16 and must have 

radios capable of tuning to the VHF simplex channel 22A. Typical coverage is 25 nm offshore.

10.3.2. Medium Frequency Radiotelephone (Voice).

The USCG broadcasts offshore forecasts and storm warnings of interest to mariners on 2670 

kHz, after first being announced on the distress, safety, and calling frequency 2182 kHz. 

10.3.3 NOAA Weather Radio.

The NOAA Weather Radio network continually broadcasts coastal and marine forecasts on 

frequencies near 162 MHZ. Recorded voice broadcasts have largely been supplanted by a 

synthesized voice. The network provides near-continuous coverage of the coastal U.S., Great 

Lakes, Hawaii, Guam, Commonwealth of the Northern Mariana Islands, and the populated 

Alaska coastline. Typical coverage is 25 nm offshore.

10.4. High Seas Broadcasts.

NWS high seas weather forecasts and warnings are also available on the following high 

frequency (HF) broadcasts.

10.4.1. HF Radiotelephone (Voice).

Weather forecasts and warnings for high seas and offshore areas are broadcast over 

scheduled HF single sideband (SSB) radiotelephone channels from USCG communications 

stations using a very distinctive and recognizable computer-synthesized voice.

10.4.2. HF Radiofacsimile.

The USCG broadcasts NWS high seas weather maps from five communications stations--

Boston, MA (NMF); Point Reyes, CA (NMC); New Orleans, LA (NMG), Honolulu, HI (KVM70) (a DOD station); and Kodiak, AK (NOJ). Limited satellite imagery, sea surface temperature 

maps, and text forecasts are also available.

10.4.3. HF Radiotelex (HF SITOR).

High seas forecasts in text format, recognized by the GMDSS, are broadcast over scheduled 

GMDSS HF narrow-band direct printing channels from USCG communications stations. Limited 

offshore forecasts are also available.
10-3

10.4.4. WWV, WWVH HF Voice (Time Tick).

Atlantic high seas warnings are broadcast at 7 and 8 minutes past the hour over WWV (Boulder, 

CO) on the following HF frequencies: 2.5, 5, 10, 15, and 20 MHZ; Pacific high seas warnings 

are broadcast at 9 minutes past the hour. Pacific high seas warnings are broadcast from 48-51 

minutes past the hour over WWVH (Honolulu, HI) at 2.5, 5, 10, and 15 MHZ. These are the 

National Institute of Standards and Technology (NIST) standard time/frequency broadcasts.

10.5. Additional Information.

Further information concerning these and other marine broadcasts, including schedules, 

frequencies, and links to products can be found at:

• www.nws.noaa.gov/om/marine/home.htm

• http://www.navcen.uscg.gov/?pageName=maritimeTelecomms

In addition, the National Geospatial-Intelligence Agency (NGA), Publication 117, Radio

Navigational Aids (http://msi.nga.mil/NGAPortal/MSI.portal; click on “Publications;” from 

Menu Options, select “Radio Navigational Aids”), contains detailed information on maritime 

safety information broadcasts within the U.S. and worldwide.
10-4
11-1 

CHAPTER 11: PUBLICITY

11.1. News Media Releases. News media releases, other than warnings and advisories, 

for the purpose of informing the public of the operational and research activities of the 

Departments of Commerce, Defense, and Transportation should reflect the joint effort of these 

agencies by giving due credit to the participation of other agencies. 

11.2. Distribution. Copies of these releases should be forwarded to the following agencies: 

• NOAA Office of Public Affairs 

Herbert C. Hoover Building 

14th and Constitution Avenue, N.W. 

Washington, DC 20230 

• Commander, Naval Meteorology and Oceanography Command 

1100 Balch Boulevard

Stennis Space Center, MS 39522-3001 

• HQ Air Force Reserve Command (AFRC/PA) 

Robins AFB, GA 31093 

• Joint Staff Weather Officer

The Joint Chiefs of Staff (J3/DDGO-ROD)

Pentagon Room 2D-921G 

Washington, DC 20318-3000 

• Federal Aviation Administration (APA-310) 

800 Independence Avenue, S.W. 

Washington, DC 20591 

• Director, NOAA Aircraft Operations Center

P.O. Box 6829 

MacDill AFB, FL 33608-0829 

• The Office of the Federal Coordinator for Meteorological Services and Supporting Research 

1325 East West Highway, Suite 7130 

Silver Spring, MD 20910 
11-2 
A-1

APPENDIX A: LOCAL NATIONAL WEATHER SERVICE 

(NWS) OFFICE PRODUCTS

A.1. General. This appendix briefly describes some of the products issued by local National 

Weather Service (NWS) offices which support the tropical cyclone forecasting and warning 

program. Additional details of all the products can be found in National Weather Service 

Instruction 10-601, located at http://www.nws.noaa.gov/directives/sym/pd01006001curr.pdf.

A.2. Products.

A.2.1. Hurricane/Typhoon Local Statements (HLS).

WFOs with coastal county responsibilities and selected inland WFOs will issue these products 

which are very specific and designed to inform media, local decision makers, and the public on 

present and anticipated storm effects in their county warning area (CWA) and adjacent coastal 

waters. HLSs will add localized details to tropical cyclone center’s advisory releases and should 

not conflict with or repeat advisory information not directly applicable to the local office’s 

CWA.

Coastal WFOs are defined as those having at least one county with significant tidal influences. 

Those are:

EASTERN REGION SOUTHERN 

REGION WESTERN REGION PACIFIC REGION

Caribou, ME

Portland, ME

Boston, MA

New York City, NY

Philadelphia, PA

Baltimore, MD/

Washington, DC

Wakefield, VA

Newport/

Morehead City, NC

Wilmington, NC

Charleston, SC

Brownsville, TX

Corpus Christi, TX

Houston/Galveston, 

TX

Lake Charles, LA

New Orleans, LA

Mobile, AL

Tallahassee, FL

Tampa Bay, FL

Miami, FL

Key West, FL

Melbourne, FL

Jacksonville, FL

San Juan, PR

San Diego, CA

Los Angeles/

Oxnard, CA

Honolulu, HI

Guam

WSO Pago Pago,

American Samoa
A-2

A.2.2. Extreme Wind Warning (EWW).

Short duration warnings are issued by WFOs to protect lives and property. WFO forecasters 

issue short duration EWW products to provide the public with advance notice of the onset of 

extreme tropical cyclone winds, usually associated with the eyewall of a major (category 3 or 

higher) tropical cyclone. Extreme Wind Warnings inform the public of the need to take 

immediate shelter in an interior portion of a well-built structure due to the onset of extreme 

tropical cyclone winds.

A.2.3. Post-Tropical Cyclone Reports (PSH).

The PSH is the primary WFO post tropical cyclone product issued to the public to report and 

document local tropical cyclone impacts. The PSH product is intended to provide the NHC, 

NWS Headquarters, the media, the public, and emergency management officials with a record of 

peak tropical cyclone conditions. This data is then used to formulate other post-event reports, 

news articles and historical records.
B-1 

APPENDIX B: DEFINING POINTS FOR TROPICAL 

CYCLONE WATCHES/WARNINGS

The coastal areas placed under tropical storm and hurricane/typhoon watches and warnings are 

described through the use of "breakpoints" or geographical positions. The National Weather 

Service (NWS) designates the locations along the U.S. East, Gulf, and California coasts, Puerto 

Rico, and Hawaii. Individual countries across the Caribbean, Central America, and South 

America provide coastal locations for their areas of responsibility to the NWS for the National 

Hurricane Center's use in tropical cyclone advisories when watches/warnings are issued by 

international partners. Beginning in 2015, the NWS will be conveying the approximate lateral 

extent of areas at risk for life-threatening storm surge in its text products using fixed 

'communication points', similar to the breakpoints used to convey the tropical cyclone watches 

and warnings. The tropical cyclone warning breakpoints will also serve as surge communication 

points, with additional surge communication points. A Graphical representation of the 

breakpoints and storm surge communication points can be found at: 

http://www.nhc.noaa.gov/breakpoints/. An additional source for tropical storm and hurricane 

watch and warning breakpoint information is NWS Instruction 10-605, located at 

http://www.nws.noaa.gov/directives/sym/pd01006005curr.pdf.
B-2 
C-1

APPENDIX C: JOINT TYPHOON WARNING CENTER 

(JTWC) BULLETINS

Below are the abbreviated communications headers and titles for the products for which JTWC is 

responsible. A brief description of each product, to include scheduled transmission times, is available 

http://www.usno.navy.mil/JTWC/products-and-services-notice.

ABIO10 PGTW Significant Weather Advisory, Indian Ocean

ABPW10 PGTW Significant Weather Advisory, Western Pacific Ocean

WTPN21-26 PGTW Tropical Cyclone Formation Alert, Northwest Pacific Ocean

WTPN31-36 PGTW Tropical Cyclone Warning, Northwest Pacific Ocean

WDPN31-36 PGTW Prognostic Reasoning Bulletin, Northwest Pacific Ocean

WTIO21-25 PGTW Tropical Cyclone Formation Alert, North Indian Ocean

WTIO31-35 PGTW Tropical Cyclone Warning, North Indian Ocean

WTPS21-25 PGTW Tropical Cyclone Formation Alert, Southwest Pacific Ocean

WTPS31-35 PGTW Tropical Cyclone Warning, Southwest Pacific Ocean

WTXS21-26 PGTW Tropical Cyclone Formation Alert, South Indian Ocean

WTXS31-36 PGTW Tropical Cyclone Warning, South Indian Ocean

WTPN21-25 PHNC Tropical Cyclone Formation Alert, Northeast Pacific Ocean

WTPN31-35 PHNC Tropical Cyclone Warning, Northeast Pacific Ocean

FKPN31-35 PHNC Prognostic Reasoning Bulletin, Northeast Pacific Ocean

WTPS21-25 PHNC Tropical Cyclone Formation Alert, Southeast Pacific Ocean

WTPS31-35 PHNC Tropical Cyclone Warning, Southeast Pacific Ocean

TPPN10-19 PGTW Tropical Cyclone Position and Intensity, Northwest Pacific Ocean

TPIO10-19 PGTW Tropical Cyclone Position and Intensity, North Indian Ocean

TPPS10-19 PGTW Tropical Cyclone Position and Intensity, Southwest Pacific Ocean

TPXS10-19 PGTW Tropical Cyclone Position and Intensity, Southern Indian Ocean

TPPZ01-05 PGTW Tropical Cyclone Position and Intensity, Central North Pacific Ocean
C-2 
D-1 

APPENDIX D: FORMAT FOR NHOP/NWSOP FLIGHT 

INFORMATION FOR INTERNATIONAL AND 

DOMESTIC NOTAM ISSUANCE

Flight information shall be sent to the NOTAM office via facsimile for dissemination as an 

International and Domestic NOTAM in the following format (Note: The request is made for a 

domestic NOTAM which will then automatically makes its way into the international NOTAM 

system):

HEADER

Request a Domestic NOTAM be Issued

A. Affected Center(s). This field will include all affected ARTCCs in 3-letter identifier 

format; e.g., ZNY, ZOA, ZAN. Synoptic track flights will probably utilize more than one 

ARTCC, and any adjacent ARTCC should be included when the flight track is within 100 

miles of the adjacent center’s airspace. Flights that are flying in the storm environment 

will utilize the ARTCC whose airspace is mostly affected.

B. Start Time (YYMMDDZZZZ). For example, 0006011600. This time would correspond to 

the entry time on a reconnaissance track or time at the storm fix latitude/longitude.

C. Ending Time (YYMMDDZZZZ). This would be the completion time of reconnaissance 

track or the time exiting the storm environment.

E.* Text. This field is free form and should include the following information: route of flight 

for the mission portion (latitude/longitude, fixes, airways), type of activity (laser, 

dropsonde, etc.), frequency/location of deployment, broadcast frequencies, any other 

pertinent information that may concern other flights. Include a unit/agency phone number 

and point of contact for possible questions. 

F. Lower Altitude (during mission). Use “Surface” since the dropsonde is the “reason” for 

the NOTAM as much or more so than the aircraft altitude.

G. Upper Altitude (during mission). For example, FL450. 

If only one altitude is to be used, then F and G may be combined. If altitude is going to 

vary throughout the mission, utilize “see text” and the information can be inserted there 

and the altitudes may be explained in field E. 

* Note that there is no paragraph “D”. It is reserved for FAA use. 

NOTES: 

1. Only ICAO approved contractions may be used. 

2. Using this format will help ensure timely and accurate information dissemination.
D-2 
E-1 

APPENDIX E: SAFFIR-SIMPSON HURRICANE WIND 

SCALE

The Saffir-Simpson Hurricane Wind Scale (SSHWS) is a scale on a 1 to 5 categorization based 

on the hurricane's intensity at the indicated time. The scale provides examples of the type of 

damages and impacts associated with winds of the indicated intensity. In general, damage rises 

by a factor of four for every category increase. The maximum sustained surface wind peak (peak 

1-minute wind at the standard meteorological observation height of 10 m [33 ft] over 

unobstructed exposure) associated with the cyclone is the determining factor in the scale. (Note 

that sustained winds can be stronger in hilly or mountain terrain compared with that experienced 

over flat terrain). Details for the Atlantic and Eastern Pacific Hurricane Basins and Central 

Pacific Hurricane Basin regarding the SSHWS can be found at the web sites indicated below.

Atlantic and Eastern Pacific Hurricane Basins: http://www.nhc.noaa.gov/aboutsshws.php. 

Central Pacific Hurricane Basin: http://www.prh.noaa.gov/cphc/pages/aboutsshs.php. 
E-2 
F-1

APPENDIX F: OFFICIAL INTERAGENCY 

AGREEMENTS

The following enclosure is the Memorandum of Agreement (MOA) between the Air Force 

Reserve Command (AFRC), the National Oceanic and Atmospheric Administration (NOAA), 

and the Federal Aviation Administration (FAA), effective April 13, 2016. The purpose of this 

agreement is to establish policies, principles, and procedures under which the AFRC, NOAA, 

and FAA provide aircraft weather reconnaissance and surveillance in support of NOAA’s 

tropical cyclone forecast, warning, and research missions.
F-2
F-3

MEMORANDUM OF AGREEMENT

BETWEEN THE 

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION AIRCRAFT 

OPERATIONS CENTER, U.S. AIR FORCE RESERVE COMMAND 53RD WEATHER 

RECONNAISSANCE SQUADRON, 

AND

THE FEDERAL AVIATION ADMINISTRATION AIR TRAFFIC ORGANIZATION

IN SUPPORT OF THE NATIONAL HURRICANE OPERATIONS PLAN 

A. PURPOSE: The purpose of this Memorandum of Agreement (MOA) is to establish 

responsibilities for the National Oceanic and Atmospheric Administration (NOAA) Aircraft 

Operations Center (AOC), U.S. Air Force Reserve Command (AFRC) 53rd Weather 

Reconnaissance Squadron (WRS), and the Federal Aviation Administration (FAA) Air 

Traffic Organization (ATO), which are hereinafter referred to as the “Parties”, to enable 

NOAA AOC and the 53rd WRS to assume the responsibility for separating participating 

manned aircraft conducting storm tracking operations within a Weather Reconnaissance Area 

(WRA). The procedures and agreements contained herein, which apply to the Atlantic 

Ocean, Gulf of Mexico, Caribbean Sea, and the Pacific Ocean, are operationally executed 

through Letters of Agreement (LOA) between responsible Air Traffic Control (ATC) 

facilities and the NOAA AOC, 53rd WRS, and, as applicable, Using Agencies. 

B. AUTHORITY: The NOAA AOC enters into this MOA under the authority of the Weather 

Service Organic Act, 15 United States Code (USC) § 313 and 49 USC § 44720. The AFRC

53rd WRS enters into this MOA under the authority of the National Hurricane Operations 

Plan (NHOP).. The FAA enters into this MOA under the authority of 49 USC § 106(f) and 

§106(m).

C. BACKGROUND: The Department of Commerce, through NOAA, is charged with the overall 

responsibility to implement a responsive, effective national tropical cyclone warning service, 

including weather reconnaissance/research flights. The AFRC, through the 53rd WRS, and 

the U.S. Department of Transportation, through the FAA, also play roles in this NOAA led

mission. The roles and responsibilities of these agencies are codified in the NHOP and in 

this MOA. 

D. DEFINITIONS:

1. A Weather Reconnaissance Area (WRA) is airspace with defined dimensions and 

published by Notice to Airmen (NOTAM), which is established to support weather 

reconnaissance/research flights. ATC services are not provided within WRAs.1 Only 

participating weather reconnaissance/research aircraft from NOAA AOC and 53rd WRS 

are permitted to operate within a WRA. 

2. A “Participating Aircraft” is defined for the purposes of this MOA and related 

documents2

as a NOAA AOC/53rd WRS manned aircraft listed in the Tropical Cyclone 

Plan of the Day (TCPOD) or tasked with an unscheduled operational mission that is 

conducted in a WRA. 

 1 The FAA may provide ATC services to participating flights in transit to and from WRAs, but will not provide ATC services, specifically 

including separation, to these flights within a WRA.

2 Including the NHOP’s Chapter 6 and any executing LOAs.
F-4

E. ACTIVITIES: Activities covered under this MOA are limited to NOAA AOC and AFRC 53rd

WRS manned flight operations conducted in accordance with the NHOP, applicable LOAs,

and as described in a published NOTAM for a WRA.

NOTE- Unmanned Aircraft Systems (UAS) operations are conducted in accordance with the 

applicable Certificate of Waiver or Authorization (COA) and are not permitted to participate 

with manned aircraft within a WRA.

F. RESPONSIBILITIES: 

1. NOAA AOC must:

(a) Enter into LOAs (using the template provided in attachment 1) with ATC facilities, 

the 53rd WRS, and, as applicable, the appropriate Special Use Airspace (SUA) using 

agencies.

(b) Provide coordinated procedures and training for aircrews of NOAA AOC

participating aircraft to operate in a WRA. These procedures must include, but not be 

limited to: minimum lateral and vertical separation, methods of determining such 

separation, and aircraft-to-aircraft communication phraseology when operating in a 

WRA.

(c) Provide procedures and training for aircrews of NOAA AOC participating aircraft to 

use communication, navigation and surveillance (CNS) equipment that will support 

safe operations within a WRA. 

(d) Identify aircraft and define minimum functioning CNS equipment that must be used 

under this MOA. 

(e) Ensure the appropriate separation procedures, described in paragraph G of this MOA,

for use within specific WRAs are briefed to aircrews of NOAA AOC participating 

aircraft.

2. AFRC 53rd WRS must:

(a) Enter into LOAs (using the template provided in attachment 1)with ATC facilities, 

the NOAA AOC, and, as applicable, the appropriate Special Use Airspace (SUA) 

using agencies.

(b) Provide coordinated procedures and training for 53rd WRS aircrews to operate in a 

WRA. These procedures must include, but not be limited to: minimum lateral and 

vertical separation, methods of determining such separation, and aircraft-to-aircraft 

communications phraseology when operating in a WRA.

(c) Provide procedures and training for 53rd WRS aircrews to use communication, 

navigation and surveillance (CNS) equipment that will support safe operations within 

a WRA. 

(d) Identify aircraft and define minimum functioning CNS equipment that must be used 

under this MOA. 

(e) Ensure the appropriate separation procedures, described in paragraph G of this MOA,

for use within specific WRAs are briefed to aircrews of 53rd WRS participating 

aircraft.
F-5

3. FAA must: 

(a) Enter into LOAs (using the template provided in attachment 1) with NOAA AOC, the 

AFRC 53rd WRS, and, as applicable, the appropriate Special Use Airspace (SUA) 

using agencies. This action will be taken by ATC facilities that are responsible for 

airspace in which the participating aircraft will operate.

(b) Receive and coordinate WRA NOTAM request.

(c) Issue WRA NOTAMs in support of the NHOP (using the template provided in 

attachment 2).

(d Provide ATC services to participating aircraft in accordance with FAA Order 

7110.65, Air Traffic Control, FAA Order 7610.4, Special Operations, and appropriate 

LOAs in support of NHOP as follows:

(1) Until participating aircraft report entering the NOTAM-defined WRA NOTAM 

airspace; and

(2) When participating aircraft report exiting the NOTAM-defined WRA airspace.

(e) Prevent non-participating aircraft receiving ATC services from entering the WRA 

during the effective time of the WRA as published in the NOTAM.

G. PROCEDURES:

1. Chief Aerial Reconnaissance Coordination All Hurricanes (CARCAH): The CARCAH 

must advise aircrews when participating aircraft will be in the WRA and brief call signs 

and mission information.

2. WRA NOTAM Request:

(a) NOAA AOC, 53rd WRS, or CARCAH must submit, in accordance with the NHOP, a 

request for a WRA NOTAM to the en route ATC facility,3 which is responsible for 

the airspace in which the subject weather reconnaissance/research flights will be 

operated, and the Air Traffic Control System Command Center (ATCSCC) as soon as 

practical prior to the start of the mission. The request must contain detailed 

information regarding the geographic definition of the WRA and altitude information.

(b) NOAA AOC, 53rd WRS, or CARCAH must coordinate with the en route ATC 

facility, which received and agreed to support the aforementioned request, and the 

ATCSCC, to request FAA support of any proposed changes to the defined WRA.

3. Flight Plan Filing: Participating aircraft must file a flight plan, as soon as practicable, 

that includes a delay time in the WRA. Failure to include a delay time will result in flight 

plan cancellation.

4. Participitating Aircraft Arrival to a WRA:

(a) Participating aircraft must use ATC services in transit to and from the WRA.

(b) Prior to entering the WRA, the arriving aircraft must obtain the position and altitude 

of each aircraft already in the WRA and verify the defined dimensions of the WRA, 

including center coordinates and maximum radius.

 3 Specifically includes FAA Air Route Traffic Control Centers (ARTCC), Center Radar Approach Controls (CERAP), and, in select cases, 

Combined Control Facilities (CCF) such as the Honolulu Control Facility (HCF).
F-6

(c) Arriving aircraft will enter the WRA at FL150,4 unless otherwise coordinated with 

ATC and the other participating aircraft.

5. Participating Aircraft Operations within a WRA: The following actions will be taken by

aircraft, in accordance with NHOP, to de-conflict operations and enhance situational 

awareness with other aircraft while operating within a WRA:

(a) Set 29.92 (inches Hg) in at least one pressure altimeter per aircraft.

(b) Contact (Primary: VHF 123.05 MHZ; Secondary: UHF 304.8 MHZ; Back-up: HF 

4701 KHz) the other participating aircraft and confirm, at a minimum, the pressure 

altitude, location relative to the WRA center point position, true heading, and 

operating altitudes.

(c) Monitor the contact frequencies indicated above during the duration of the flight and 

maintain communication with all other participating aircraft at all times.

(d) The WRA center coordinates will be used for the duration of the flight. If a WRA is 

moved due to operational reasons, a different WRA center point will be coordinated 

between all participating aircraft and impacted ATC facilities as soon as possible.

(e) If any aircraft is unable to maintain assigned altitude(s), immediately notify all 

participating aircraft and take actions to ensure sufficient vertical and/or lateral 

separation is maintained or attained as soon as practical.

(f) Use “see and avoid” principles to the maximum extent possible within the WRA. 

Aircraft must periodically broadcast GPS position reports to other participating 

aircraft within the WRA and use air-to-air TACAN and cockpit displays/maps to 

maintain awareness of other aircraft locations.

6. Separation between participating aircraft within a WRA:

(a) Aircraft 10 NM or more from other aircraft operating in the same WRA must 

maintain vertical separation within the WRA of at least 1,000 feet between their 

operating altitudes or block altitudes, or as specified in the applicable LOA.

(b) Aircraft less than 10 NM from other aircraft operating in the same WRA, must apply 

vertical separation of at least 2,000 feet between operating altitudes or block altitudes, 

or as specified in the applicable LOA. Aircraft may use air-to-air TACAN and TCAS 

to assist with visual acquisition. Reduced vertical separation may be applied with 

concurrence from other aircraft within the WRA.

NOTE- The 53Rd WRS may apply Military Assumes Responsibility for Separation of Aircraft 

(MARSA), in accordance with FAA Order 7110.65 and FAA Order 7610.4, between 53rd WRS 

aircraft within the WRA. MARSA may not be applied between 53rd WRS aircraft and NOAA 

AOC aircraft.

7. Altitude changes between participating aircraft within the WRA:

(a) Aircraft must initiate communications with each other prior to altitude changes and 

maintain two-way aircraft-to-aircraft communications throughout the duration of the 

altitude change.

 4 The upper limit of WRAs may be negotiated between NOAA AOC, 53rd WRS, and the responsible FAA en route ATC. While the template 

NOTAM indicates SFC-15,000 feet, the WRA ceiling may be lowered, especially when established closer to land where ATC services are 

provided at lower altitudes.
F-7

(b) Aircraft must ensure positive lateral separation (in accordance with sub-paragraphs 

(d), (e), and (f) in this section) prior to descending or climbing through the altitude(s) 

of other aircraft by reference to the WRA center point using the appropriate aircraft 

navigation systems.

(c) An altitude change is complete when the aircraft changing altitude advises the other 

aircraft, and receives an acknowledgement, that the altitude to which it was climbing 

or descending is reached and maintained.

(d) Aircraft that are not in visual contact and separated by 30NM or more, as indicated by 

the appropriate aircraft navigation systems, may transition through the altitude of 

other participating aircraft.

(e) Aircraft that are not in visual contact and separated by less than 30 NM, as indicated 

by the appropriate aircraft navigation systems, must confirm with each other that they 

are not on converging courses prior to an altitude change. 

(f) Aircraft that are in visual contact may apply visual separation in accordance with the 

following procedures: 

(1) The aircraft that initiates visual separation must advise the other aircraft that the 

aircraft is in sight and will maintain visual separation from it. 

(2) The observed aircraft must acknowledge the use of visual separation by the 

initiating aircraft prior to the altitude change.

(3) The aircraft changing altitude must advise the other aircraft upon reaching and 

maintaining the altitude to which it was climbing or descending.

(4) Visual separation may be discontinued when the altitude change is complete 

according to sub-paragraph (c) in this section.

8. Participating Aircraft Departure from a WRA:

(a) Prior to departing the WRA, aircraft will establish communications with the 

appropriate ATC facility and request an IFR clearance.

(b) Prior to departing the WRA, aircraft will verify and maintain vertical and lateral

separation from other participating aircraft in the WRA.

(c) Aircraft will depart the WRA at FL140, unless otherwise coordinated with ATC and 

other aircraft in the WRA.5

(d) Departing aircraft will report, “leaving (tropical activity name) WRA,” to other 

aircraft in the WRA.

NOTE- The tropical activity name (as identified by the National Hurricane Center) provides 

identification of the WRA. Examples: Isabelle WRA, Sandy WRA, Tropical Storm Emily WRA, 

etc.

(e) Should an aircraft lose communications with the other participating aircraft within a 

WRA, it will maintain the last altitude that was coordinated with the other aircraft 

until it departs the WRA.

(f) If navigation systems become unreliable, the flight crew will terminate the mission 

and depart the WRA at the last coordinated altitude, or as coordinated with ATC if 

radio communications are available.

 5 See footnote 4 for information on WRAs with lowered ceilings.
F-8

H. FUNDS AND OTHER RESOURCES: This MOA neither documents nor provides for the 

exchange of funds or other resources, including personnel, among the Parties, nor does it 

make any commitment of funds or other resources. Each Party makes appropriate resource 

and funding decisions under their own authorities in order to maximize the benefits of the 

partnership and cooperation under this MOA. 

I. PERSONNEL: Each Party is responsible for all costs of its personnel engaged in activiuties 

covered by this MOA, including pay and benefits, support, and travel. Each Party is 

responsible for supervision and management of its personnel. 

J. GENERAL PROVISIONS:

1. This MOA supersedes any existing MOAs, memorandums of agreement, or other 

agreements between the Parties, insofar as any such document is inconsistent with this 

MOA.

2. Nothing in this MOA is intended nor may be construed to limit or affect in any way the 

authority or legal responsibilities of the Parties.

3. Nothing in this MOA is intended nor may be construed to obligate the Parties to any 

current or future expenditure of resources in advance of the availability of appropriations 

from Congress. This MOA does not obligate the Parties to expend funds on any 

particular activity, even if funds are available. 

4. Specific activities implemented pursuant to this MOA that involve the transfer of funds, 

services, or property between the Parties will require the execution of separate 

agreements.

5. POINTS OF CONTACT: The following points of contact will be used by the Parties to 

communicate in the implementation of this MOA. Each Party may change its point of 

contact upon reasonable notice to the other Party. 

(a) FOR NOAA AOC: Commanding Officer, Aircraft Operations Center

(b) FOR AFRC 53rd WRS: Commander, 403rd Operations Group

(c) FOR FAA ATO: Manager, Strategic Operations Security 

6. This MOA is not transferrable.

K. DURATION AND MODIFICATIONS: This MOA shall remain in effect unless cancelled by one 

of the Parties. This MOA may be jointly reviewed upon request by a signatory Party, and 

may be modified by mutual written consent of the undersigned. Joint reviews should be 

completed prior to the annual Interdepartmental Hurricane Conference.

L. EFFECTIVE DATE: This MOA becomes effective beginning on the day after the last Party 

signs.
F-9

Attachments

1. WRA Letter of Agreement Template

2. WRA NOTAM Template

APPROVED:

____//SIGNED//________________________ _7 April 2016__

Robert H. Sweet Date

Manager (Acting), Strategic Operations Security, 

Air Traffic Organization, System Operations Security

Federal Aviation Administration

____//SIGNED//________________________ ___4/7/2016___ 

Anthony Tisdall Date

Air Traffic Manager, Air Traffic Control System Command Center

Air Traffic Organization, System Operations Services

Federal Aviation Administration

____//SIGNED//_________________________ _11 APR16____ 

Captain Michael Silah Date

Commanding Officer, Aircraft Operations Center

National Oceanic and Atmospheric Administration

____//SIGNED//_________________________ __12 APR 2016_

Colonel David J. Condit Date

Commander, 403rd Operations Group

U.S. Air Force Reserve Command
F-10

ATTACHMENT 1

LETTER OF AGREEMENT TEMPLATE

BETWEEN

[INSERT NAME AND LOCATION ID OF FAA EN ROUTE ATC FACILITY OR 

FACILITIES]

AND THE

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION AIRCRAFT 

OPERATIONS CENTER AND

U.S. AIR FORCE RESERVE COMMAND 53RD WEATHER RECONNAISSANCE 

SQUADRON

SUBJECT: PARTICIPATING WEATHER RECONNAISSANCE / RESEARCH AIRCRAFT 

OPERATIONS WITHIN WEATHER RECONNAISSANCE AREAS 

1. PURPOSE: To define responsibilities and procedures for the National Oceanic and 

Atmospheric Administration (NOAA) Aircraft Operations Center (AOC) and the U.S. Air 

Force Reserve Command (AFRC) 53rd Weather Reconnaissance Squadron (53rd WRS ) to 

conduct weather reconnaissance/research operations with participating manned aircraft in a 

Weather Reconnaissance Area (WRA) within the Flight Information Region (FIR) of the 

Federal Aviation Administration (FAA) Air Traffic Control (ATC) facility or facilities 

identified in paragraph two of this Letter of Agreement (LOA). 

2. SCOPE: This LOA is applicable to [insert name and location ID of ATC facility or 

facilities], NOAA AOC, and the 53rd WRS. The provisions of this LOA are only applicable 

in United States controlled FIRs.

3. AUTHORITY: [insert location ID of ATC facility or facilities], NOAA AOC, and 53rd WRS 

enter into this agreement under the authority of the trilateral Memorandum of Agreement 

(MOA), Memorandum of Agreement Between the National Oceanic and Atmospheric 

Administration Aircraft Operations Center, U.S. Air Force Reserve Command 53rd Weather 

Reconnaissance Squadron, and the Federal Aviation Administration Air Traffic Organization 

in Support of the National Hurricane Operations Plan.

4. RESPONSIBILITIES: 

a. The NOAA AOC and 53rd WRS must:

(1) Ensure that all operations personnel are briefed on the provisions of this LOA.

(2) Submit, when logistically possible, a pre-planning package to [insert location ID of 

ATC facility or facilities] and the Air Traffic Control System Command Center 

(ATCSCC) a minimum 2 hours prior to planned mission start. The package should 

contain information on aircraft call signs, beacon codes, geographic definition of 

proposed mission area, and other pertinent mission information.

(3) Submit a WRA Notice to Airmen (NOTAM) request to the en route ATC facility6

, 

which is responsible for the airspace in which the weather reconnaissance/research 

 6 Specifically includes FAA Air Route Traffic Control Centers, Center Radar Approach Controls (CERAP), and, in select cases, Combined 

Control Facilities (CCF) such as the Honolulu Control Facility (HCF).
F-11

flight will be operated, and the Air Traffic Control System Command Center 

(ATCSCC) as soon as practical prior to the start of mission. The request must 

contain detailed information regarding the geographic definition and altitude 

information of the WRA.

(4) Coordinate with the responsible en route ATC facility and the ATCSCC to request 

FAA support of any proposed changes to the defined WRA.

(5) Ensure that pilots operating under the provisions of this LOA are responsible for 

remaining within the vertical and lateral confines of the airspace as defined in the 

published WRA NOTAM.

(6) Ensure that pilots understand their responsibility for separation from Visual Flight 

Rules (VFR) and Instrument Flight Rules (IFR) aircraft operating in uncontrolled 

airspace.

NOTE: Operations within offshore and oceanic airspace include areas of 

uncontrolled airspace. Aircraft may encounter non-participating, untracked 

aircraft operating under VFR or IFR at and below 5,500 feet MSL.

b. [insert location ID of ATC facility or facilities] must:

(1) Ensure that all ATC personnel are briefed on the provisions of this LOA.

(2) Review the Tropical Cyclone Plan of the Day (TCPOD) at 

www.nhc.noaa.gov/reconlist.shtml by 1830 UTC. 

(3) Coordinate, as necessary, with other affected ATC facilities to ensure a complete 

understanding of each facility’s responsibilities and procedures.

(4) Coordinate requested WRAs with the NOAA AOC, 53rd WRS, and impacted 

Special Use Airspace (SUA) Using Agencies.

NOTE –SUA Using Agencies determine if Department of Defense (DOD) 

operational requirements are compatible with the establishment of a WRA and 

should define de-confliction procedures for SUA that may not be released.

(5) Establish WRAs by published NOTAMs.

(6) Prevent non-participating aircraft receiving ATC services from entering the WRA 

during the effective time of the WRA as published in the NOTAM.

(7) Submit a signed copy of the LOA to ATO System Operations Security (9-ATORHQ-IFOS@faa.gov) for recordkeeping purposes. 

5. PROCEDURES: 

a. [insert location ID of ATC facility or facilities] Procedures: 

(1) Provide ATC services to and from the WRA in accordance with FAA Order 

7110.65, Air Traffic Control, FAA Order 7610.4, Special Operations, the trilateral 

MOA cited in Section 3 of this LOA, and applicable ATC facility Standard 

Operating Procedures (SOP).

(2) Provide NOAA AOC and 53rd WRS participating aircraft with a clearance into the 

WRA in accordance with the trilateral MOA cited in Section 3 of this LOA.

(3) Provide an IFR clearance to participating aircraft requesting to depart the WRA. 
F-12

b. Participating Aircraft Procedures: Pilots request entry to and departure from the WRA 

according to the trilateral MOA cited in Section 3 of this LOA.

6. DURATION AND MODIFICATIONS: This LOA shall remain in effect unless cancelled by one of 

the Parties. This LOA may be jointly reviewed upon request by either Party, and may be 

modified by mutual written consent of the undersigned.

7. EFFECTIVE DATE: This LOA becomes effective beginning on the day after the last Party signs.

APPROVED BY:

________________________________________ _________________

(Name) Date

Air Traffic Manager

(ATC Facility)

________________________________________ __________________

(Name) Date

Commanding Officer, Aircraft Operations Center

National Oceanic and Atmospheric Administration

_____________________________________ _________________

(Name) Date

Commander, 403rd Operations Group,

U.S. Air Force Reserve Command

_____________________________________ _________________

(Name) Date

(Using Agency Title),

(DOD Component)
F-13

ATTACHMENT 2

WRA NOTAM TEMPLATE

!FDC X/XXXX (APPLICABLE ARTCSS(s)) (AXXXX/XX)...AIRSPACE 

(HURRICANE/TYPHOON/TROPICAL STORM) (NAME OF TROPICAL DISTURBANCE) WEATHER 

(WX) RECONNAISSANCE FLIGHTS WI THE WX RECONNAISSANCE AREA (WRA) DEFINED AS XXX

NM RADIUS OF XXXXXXNXXXXXXXW (ARTCCS/CERAPS/HCF AND SUA USING AGENCIES MUST 

COORDINATE TO PUBLISH ANY REQUIRED AIRSPACE CUT OUTS) SFC-XXX. VERTICAL 

MANEUVERING AND RELEASE OF DROPSONDES ARE EXPECTED. NONPARTICIPATING AIRCRAFT 

SHOULD AVOID THE WRA. IFR AIRCRAFT CAN EXPECT REROUTES. 

TIME-TIME

NOTES1. WRAs are not permitted over land.

2. Cut-outs should include Class B, Class C, Class D, and SUA, as applicable. 

3. Distance (NM) for the WRA radius must be coordinated. It will be dependent on the 

WRA location and ATC operational requirements.

4. If more than one WRA is required, the WRA boundaries must be no closer than the 

lateral separation standards required for aircraft operations defined in FAA JO 7110.65 

and Letters of Agreement.

5. WRA NOTAM must be domestic and international for widest dissemination.
F-14
G-1

APPENDIX G: RECCO, HDOB, AND TEMP DROP

CODES, TABLES, AND REGULATIONS

G.1. General. 

This appendix contains the formats and detailed explanations of encoded data messages 

transmitted by weather reconnaissance aircraft. The products include reconnaissance coded 

observations (RECCOs), high-density/high-accuracy observations (HDOBs), and dropsonde 

observations (TEMP DROP).

G.2. Aerial Reconnaissance Messages.

G.2.1. RECCO.

The RECCO message is routinely used to convey horizontal weather observations taken manually by meteorologists 

aboard USAF and NOAA weather reconnaissance aircraft. At the time of the observation the aircraft observing 

platform is considered to be located on the axis of a right vertical cylinder with a radius of 30 nautical miles 

bounded by the earth's surface and the top atmosphere. Flight level winds, temperature, dew point, and geopotential 

height values are sensed or computed and reported as occurring at the center of the observation circle. Radar 

echoes, significant weather changes, distant weather, icing, and cloud coverage, types, and amounts are phenomena 

that may also be observed and reported. Code groups identifying these phenomena may be reported as necessary to 

adequately describe the meteorological conditions observed. All geopotential computations are made relative to the 

1976 US Standard Atmosphere (adjustable altimeters set to 29.92 inches Hg). Since all height reports are in units of 

geopotential by convention of the World Meteorological Organization, pressure surface height reports from 

reconnaissance aircraft are in geopotential units.

Sample USAFR/53 WRS and NOAA RECCO messages are shown in Figure G-1. A breakdown of these messages 

is provided in Tables G-1 and G-2. Figure G-2 shows the standard RECCO recording form worksheet with each 

element described in Table G-3 and regulations explained in Table G-4.

URNT11 KNHC 041322

97779 13204 10295 56518 30500 22068 10089 /3051

42045

RMK AF305 1511A JOAQUIN OB 13

SWS = 41KTS

URNT11 KWBC 202029

97779 20284 50267 72800 04500 14009 24218 /0004 41311 93273

RMK NOAA3 01GGA INVEST OB 10

Figure G-1. Example USAF and NOAA Aircraft RECCO Messages for Tropical Cyclones
G-2

Table G-1. Decoded USAF Aircraft RECCO Message

URNT11 KNHC 041322

97779 13204 10295 56518 30500 22068 10089 /3051

42045

RMK AF305 1511A JOAQUIN OB 13

SWS = 41KTS

URNT11: WMO abbreviated communications header for a RECCO taken during a 

tasked invest, tropical cyclone, or subtropical cyclone mission in the Atlantic 

basin (see Chapter 5, paragraph 5.7.6 for details).

KNHC: ICAO of National Hurricane Center where RECCO message is received and 

disseminated (see Chapter 5, paragraph 5.7.6 for details).

041322: RECCO transmission date and time is 4th day of the month at 1322 UTC.

97779: The 9’s in the first and last digits are standard delimiters of the first RECCO 

observation section. The middle three digits, 777, indicate that the 

observation is taken aboard an aircraft with radar capabilities (see “Table 1” 

section of Table G-3).

13204: The first four digits are the time observation is taken of 1320 UTC. The last 

digit, 4, indicates the aircraft has dew point measuring capability and is 

below 10 km (see “Table 2” section of Table G-3).

10295: The first digit, 1, indicates the observation is taken Sunday. The second 

digit, 0, indicates the observation is taken in the northern hemisphere 

between 0° and 90° W longitude (see “Table 3” section of Table G-3 and 

Figure G-3 for graphical depiction). The last three digits show the 

observation is taken at 29.5° N latitude.

56518: The first three digits show the observation is taken at 56.5° W latitude (see

Note 4 in Table G-4). The fourth digit, 1, indicates light aircraft turbulence 

(see “Table 4” section in Table G-3). The last digit, 8, indicates aircraft 

flight conditions of in and out of clouds (see “Table 5” section of Table G-3 

and Note 5 of Table G-4).

30500: The first three digits show the aircraft pressure altitude is 3050 m. The 

fourth digit, 0, indicates that the wind observation is a spot measurement (see

“Table 6” section of Table G-3). The last digit, 0, shows that the wind is 

obtained by Doppler radar or inertial systems (see “Table 7” section of Table 

G-3).

22068: Observed Flight-level wind is approximately from 220° (between 215° and 

224°) at 68 kt. Note: light and variable winds < 10 kt are encoded as 

99005.

10089: The first two digits indicate the observed flight-level temperature is 10°C. 

The next two digits indicate the flight-level dew point temperature is 8°C 

(see Note 6 of Table G-4 for encoding negative temperature values). The 
G-3

last digit, 9, indicates that there are thunderstorms within 30 nm of the 

aircraft (see “Table 8” section of Table G-3 and Note 7 of Table G-4).

/3051: The “/3” indicates an observed geopotential height measurement at 700 mb. 

The last three digits show the height of 3051 m (see “Table 9” section of 

Table G-3 and Note 8 of Table G-4).

42045: The first digit, 4, indicates a manually observed surface wind from a flight 

level of 700 mb or below. The remaining four digits show that the surface 

wind is from approximately 200° (between 195° and 204°) at 45 kt (see Note 

10 in Table G-4 for wind speeds above 130 kt). Note: light and variable 

winds < 10 kt are encoded as 99005.

RMK: Beginning of RECCO plain-language remarks section (see Note 3 of Table 

G-4).

AF305: Aircraft in mission ID is U.S. Air Force C-130J with tail number 5305 (see 

Chapter 5, Table 5-4 for details).

1511A: Index group in mission ID indicates the 15th mission of the 11th classified 

tropical or subtropical system of the year in the Atlantic basin (see Chapter 

5, Table 5-4 for details).

JOAQUIN: Official name of system in mission ID is “Joaquin” (see Chapter 5, Table 5-

4 for details).

OB 13: Observation number 13 is assigned to this RECCO (see Chapter 5, 

paragraph 5.7.8 for details).

SWS=41KTS: Observed surface wind speed measured by SFMR is 41 kt.
G-4

Table G-2. Decoded NOAA Aircraft RECCO Message

URNT11 KWBC 202029

97779 20284 50267 72800 04500 14009 24218 /0004 41311 93273

RMK NOAA3 01GGA INVEST OB 10

All items are decoded in a similar manner to the USAF Aircraft RECCO message depicted 

in Table G-1, except for the following:

/0004: The “/0” indicates an extrapolated sea-level pressure measurement. The last 

three digits show the sea-level pressure of 1004 mb (see “Table 9” section of 

Table G-3 and Note 8 of Table G-4).

93273: The first digit, 9, indicates a sea-surface temperature measurement. The 

second digit, 3, indicates that the inflight visibility is greater than 3 miles (see 

"Table 23" section of Table G-3). The last three digits show the observed 

sea-surface temperature is 27.3°C.

NOAA3: Aircraft in mission ID is NOAA WP-3D with tail number N43RF (see 

Chapter 5, Table 5-4 for details).

01GGA: Index group in mission ID indicates the first mission of the 7th unclassified 

suspect system of the year in the Atlantic basin (see Chapter 5, Table 5-4 for 

details).

INVEST: Indicates invest mission in the storm ID (see Chapter 5, Table 5-4 for 

details).

NOTE: The observed surface wind group, indicated by the first digit of 4, is placed on the same 

line as the other numeric encoded groups in a NOAA aircraft RECCO message rather than on a 

separate line.
G-5

Figure G-2. Reconnaissance Code Recording Form
G-6

Table G-3. Reconnaissance Code Tables

TABLE 1 XXX

222 Sec One Observation without radar 

capability

555 Sec Three (intermediate) 

observation with or without radar 

capability

777 Sec One Observation with radar 

capability

TABLE 2 i

d

0 No dew point capability/acft below 

10,000 meters

1 No dew point capability/acft at or 

above 10,000 meters

2 No dew point capability/acft below 

10,000 meters and flight lvl temp -

50°C or colder

3 No dew point capability/acft at or 

above 10,000 meters and flight lvl 

temp -50°C or colder

4 Dew point capability/acft below 10,000 

meters

5 Dew point capability/acft at or above 

10,000 meters

6 Dew point capability/acft below 10,000 

meters and flight lvl temp -50°C or 

colder

7 Dew point capability/acft at or above 

10,000 meters and flight lvl temp -

50°C or colder

TABLE 3 Q

0 0° -90° W Northern

1 90° W - 180° Northern

2 180° - 90° E Northern

3 90° - 0° E Northern

4 Not Used

5 0° - 90° W Southern

6 90° W - 180° Southern

7 180° - 90° E Southern

8 90° - 0° E Southern

TABLE 4 B

0 None

1 Light turbulence

2 Moderate turbulence in clear air, 

infrequent

3 Moderate turbulence in clear air, 

frequent

4 Moderate turbulence in cloud, 

infrequent

5 Moderate turbulence in cloud, 

frequent

6 Severe Turbulence in clear air, 

infrequent

7 Severe Turbulence in clear air, 

frequent

8 Severe Turbulence in cloud, 

infrequent

9 Severe Turbulence in cloud, frequent

TABLE 5 f

c

0 In the clear

8 In and out of clouds

9 In clouds all the time (continuous IMC)

/ Impossible to determine due to 

darkness or other cause

TABLE 6 dt

0 Spot of Wind

1 Average wind

/ No wind reported

TABLE 7 da

0 Winds obtained using doppler radar or 

inertial systems

1 Winds obtained using other navigation 

equipment and/or techniques

/ Navigator unable to determine or wind 

not compatible

TABLE 8 w

0 Clear

1 Scattered (trace to 4/8 cloud coverage)

2 Broken (5/8 to 7/8 cloud coverage)

3 Overcast/undercast

4 Fog, thick dust or haze

5 Drizzle

6 Rain (continuous or intermittent precip -

from stratiform clouds)

7 Snow or rain and snow mixed

8 Shower(s) (continuous or intermittent 

precip - from cumuliform clouds)

9 Thunderstorm(s)

/ Unknown for any cause, including 

darkness

TABLE 9 j

0 Sea level pressure in whole millibars

(thousands fig if any omitted)

1 Altitude 200 mb surface in geopotential 

decameters (thousands fig if any 

omitted)

2 Altitude 850 mb surface in geopotential 

meters (thousands fig omitted)

3 Altitude 700 mb surface in geopotential 

meters (thousands fig omitted)

4 Altitude 500 mb surface in geopotential 

decameters

5 Altitude 400 mb surface in geopotential 

decameters

6 Altitude 300 mb surface in geopotential 

decameters

7 Altitude 250 mb surface in geopotential 

decameters (thousands fig if any 

omitted)

8 D - Value in geopotential decameters; if 

negative 500 is added to HHH

9 Altitude 925 mb surface in geopotential 

meters

/ No absolute altitude available or 

geopotential data not within ± 30 

meters/4 mb accuracy requirements

TABLE 10 Ns

0 No additional cloud layers (place 

holder)

1 1 okta or less, but not zero

(1/8 or less sky covered)

2 2 oktas (or 2/8 of sky covered)

3 3 oktas (or 3/8 of sky covered)

4 4 oktas (or 4/8 of sky covered)

5 5 oktas (or 5/8 of sky covered)

6 6 oktas (or 6/8 of sky covered)

7 7 oktas or more but not 8 oktas

8 8 oktas or sky completely covered

9 Sky obscured (place holder)

TABLE 11 C

0 Cirrus (Ci)

1 Cirrocumulus (Cc)

2 Cirrostratus (Cs)

3 Altocumulus (Ac)

4 Altostratus (As)

5 Nimbostratus (Ns)

6 Stratocumulus (Sc)

7 Stratus (St)

8 Cumulus (Cu)

9 Cumulonimbus (Cb)

/ Cloud type unknown due to darkness 

or other analogous phenomena

TABLE 12 hshsHtHthihiHiHi

00 Less than 100

01 100 ft

02 200 ft

03 300 ft

etc, etc

49 4,900 ft

50 5,000 ft

51-55 Not used

56 6,000 ft

57 7,000 ft

etc, etc

79 29,000 ft

80 30,000 ft

81 35,000 ft

82 40,000 ft

etc, etc

89 Greater than 70,000 ft

// Unknown

TABLE 13 dw

0 No report 5 SW

1 NE 6 W

2 E 7 NW

3 SE 8 N

4 S 9 all directions

TABLE 14 Ws

0 No change

1 Marked wind shift

2 Beginning or ending or marked 

turbulence

3 Marked temperature change (not with 

altitude)

4 Precipitation begins or ends

5 Change in cloud forms

6 Fog or ice fog bank begins or ends

7 Warm front

8 Cold Front

9 Front, type not specified

TABLE 15 SbSeSs

0 No report

1 Previous position

2 Present position

3 30 nautical miles

4 60 nautical miles

5 90 nautical miles

6 120 nautical miles

7 150 nautical miles

8 180 nautical miles

9 More than 180 nautical miles

/ Unknown (not used for Ss)
G-7

Table G-3 (continued). Reconnaissance Code Tables

TABLE 16 wd

0 No report

1 Signs of a tropical cyclone

2 Ugly threatening sky

3 Duststorm or sandstorm

4 Fog or ice fog

5 Waterspout

6 Cirrostratus shield or bank

7 Altostratus or altocumulus shield or 

bank

8 Line of heavy cumulus 

9 Cumulonimbus heads or 

thunderstorms

TABLE 17 I

r

7 Light

8 Moderate

9 Severe

/ Unknown or contrails

TABLE 18 I

t

0 None

1 Rime ice in clouds

2 Clear ice in clouds

3 Combination rime and clear ice in 

clouds

4 Rime ice in precipitation

5 Clear ice in precipitation

6 Combination rime and clear ice in 

precip

7 Frost (icing in clear air)

8 Nonpersistent contrails (less than 

1/4 nautical miles long)

9 Persistent contrails

TABLE 19 Sr,Ew,El

0 0NM 5 50NM

1 10NM 6 60-80NM

2 20NM 7 80-100NM

3 30NM 8 100-150NM

4 40NM 9 Greater than 150NM

/ Unknown

TABLE 20 Oe

0 Circular

1 NNE - SSW

2 NE - SW

3 ENE - WSW

4 E - W

5 ESE - WNW

6 SE - NW

7 SSE - NNW

8 S - N

/ Unknown

TABLE 21 ce

1 Scattered Area

2 Solid Area

3 Scattered Line

4 Solid Line

5 Scattered, all quadrants

6 Solid, all quadrants

/ Unknown

TABLE 22 i

e

2 Weak

5 Moderate

8 Strong

/ Unknown

TABLE 23 Vi

1 Inflight visibility 0 to and including 1 nautical mile

2 Inflight visibility greater than 1 and not exceeding 3 nautical miles

3 Inflight visibility greater than 3 nautical miles

RECCO SYMBOLIC FORM 

SECTION ONE (MANDATORY)

9XXX9 GGggid YQLaLaLa LoLoLoBfc hahahadtda

ddfff TTTdTdw /jHHH

SECTION TWO (ADDITIONAL)

1knNsNsNs ChshsHtHt ..... ..... 4ddff

6WsSsWddw 7IrI

t

SbSe 7hihiHiHi 8drdrSrOe

8EwElcei

e 9Vi

TwTwTw

SECTION THREE (INTERMEDIATE)

9XXX9 GGggid YQLaLaLa LoLoLoBfc hahahadtda

ddfff TTTdTdw /jHHH
G-8

Table G-4. Reconnaissance Code Regulations

1. At the time of the observation the aircraft observing 

platform is considered to be located on the axis of a right 

vertical cylinder with a radius of 30 nautical miles 

bounded by the earth's surface and the top atmosphere.

Present weather, cloud amount and type, turbulence, and 

other subjective elements are reported as occurring within 

the cylinder. Flight level winds, temperature, dew point, 

and geopotential values are sensed or computed and 

reported as occurring at the center of the observation 

circle. Radar echoes, significant weather changes, distant 

weather, and icing are phenomena that may also be 

observed/reported. Code groups identifying these 

phenomena may be reported as necessary to adequately 

describe met conditions observed.

2. The intermediate observation (Section Three) is 

reported following Section One (or Section Two if 

appended to Section One) in the order that it was taken.

3. Plain language remarks may be added as appropriate.

These remarks follow the last encoded portion of the 

horizontal or vertical observation and will clearly convey 

the intended message. Vertical observations will not 

include meteorological remarks. These remarks must 

begin with a letter or word-e.g. "FL TEMP" vice "700 

MB FL TEMP." The last report plain language remarks 

are mandatory, i.e., “LAST REPORT. OBS 01 thru 08 to 

KNHC, OBS 09 and 10 to KBIX."

4. The hundreds digit of longitude is omitted for 

longitudes from 100° to 180°.

5. Describe conditions along the route of flight actually 

experienced at flight level by aircraft.

6. TT, TdTd. When encoding negative temperatures, 50 is 

added to the absolute value of the temperature with the 

hundreds figure, if any, being omitted. A temperature of -

52°C is encoded as 02, the distinction between -52°C and 

2°C being made from id. Missing or unknown 

temperatures are reported as //. When the dew point is 

colder than -49.4°C, Code TdTd as // and report the actual 

value as a plain language remark - e.g. "DEW POINT 

NEG 52°C".

7. When two or more types of w co-exist, the type with 

the higher code figure will be reported. Code Figure 1, 2 

and 3 are reported based on the total cloud amount 

through a given altitude, above or below the aircraft, and 

when other figures are inappropriate. The summation 

principle applies only when two or more cloud types 

share a given altitude.

8. When j is reported as a /, HHH is encoded as ///.

9. If the number of cloud layers reported exceeds 3, kn in 

the first 1-group reports the total number of cloud layers.

The second 1-group reports the additional number of 

layers being reported exclusive of those previously 

reported. In those cases where a cloud layer(s) is 

discernible, but a descriptive cloud picture of the 

observation circle is not possible, use appropriate remarks 

such as "Clouds Blo" or "As Blo" to indicate the presence 

of clouds. In such cases, coded entries are not made for 

group 9. The sequence in which cloud amounts are 

encoded depends upon type of cloud, cloud base, and 

vertical extent of the cloud. The cloud with the largest 

numerical value of cloud type code (C) is reported first, 

regardless of coverage, base, or vertical extent. Among 

clouds of the same cloud type code, sharing a common 

base, the cloud of greatest vertical extent is reported first.

The summation principle is not used; each layer is treated 

as though no other clouds were present. The total amount 

of clouds through one altitude shared by several clouds 

will not exceed 8 oktas. Only use code figure 0 as a place 

holder when you can determine that no additional cloud 

layers exist. In case of undercast, overcast, etc., use code 

figure 9 as a placeholder.

10. Due to limitations in the ability to distinguish sea state 

features representative of wind speeds above 130 knots,

surface wind speeds in excess of 130 knots will not be 

encoded. Wind speeds of 100 to 130 knots inclusive will 

be encoded by deleting the hundreds figure and adding 50 

to dd. For wind speeds above 130 knots, dd is reported 

without adding 50 and ff is encoded as // with a plain 

language remark added, i.e., "SFC WIND ABOVE 130 

KNOTS."

11. Significant weather changes which have occurred 

since the last observation along the track are reported for 

Ws.

12. When aircraft encounters icing in level flight, the 

height at which the icing occurred will be reported for hih

i

. The HiHi will be reported as //.
G-9

Figure G-3. Geographical Depiction of Octants Encoded in RECCO Messages

G.2.2. HDOB.

The HDOB message is used to transmit High-Density/High-Accuracy (HD/HA) meteorological 

data from hurricane reconnaissance aircraft. These are created automatically by the system 

software. Each message consists of a communications header line described in Chapter 5, 

paragraph 5.7.6, a mission/ob identifier line (Table G-5), and 20 lines of HD/HA data (Table G6).

Within an HDOB message, the time interval (resolution) between individual HD/HA 

observations can be set by the operator to be 30, 60, or 120 seconds. However, regardless of the 

time resolution of the HD/HA data, the meteorological parameters in the HDOB message always 

represent 30-second averages along the flight track (except for certain peak values as noted in 

Table G-6).

The nominal time of each HD/HA record is the midpoint of the 30-second averaging interval.

This means that an HD/HA record at time t will include data measured at time t+15 seconds. For 

purposes of determining peak flight-level and SFMR winds, the encoding interval begins 15 

seconds after the nominal time of the last HD/HA record and ends 15 seconds after the nominal 

time of the record being encoded.

A sample HDOB message is shown in Figure G-4 (message begins with URNT15...):
G-10

0 1 2 3 4 5 6 7

01234567890123456789012345678901234567890123456789012345678901234567890

-----------------------------------------------------------------------

URNT15 KNHC 281426

AF302 1712A KATRINA HDOB 41 20050928

142030 2608N 08756W 7093 03047 9333 +192 +134 133083 089 080 /// 00 

142100 2609N 08755W 7091 03054 9330 +166 +146 133106 115 103 /// 00 

142130 2610N 08754W 7058 03040 9295 +134 +134 135121 124 111 /// 00 

142200 2611N 08753W 7037 03060 9291 +124 +124 138129 136 122 /// 00 

.

.

.

142230 2612N 08752W 7010 03057 9282 +102 +102 141153 166 148 /// 00 

142300 2612N 08751W 7042 03010 9293 +088 +083 133159 164 147 /// 00 

142330 2613N 08750W 6999 03064 9279 +088 +088 138158 161 144 /// 00

142400 2614N 08749W 7005 03046 9281 +080 +080 138155 158 142 /// 00 

142430 2614N 08748W 6998 03048 9278 +078 +078 138151 153 137 /// 00 

142500 2615N 08747W 7002 03048 9279 +084 +084 140146 148 133 /// 00 

$$

Figure G-4. Example HDOB Message for Tropical Cyclones

Table G-5. Mission/Ob Identifier Line Format for HDOB Messages

A sample mission/ob identifier line is given below (beginning with AF302...), followed by a 

description of the parameters.

0 1 2 3 4 5 6 7

01234567890123456789012345678901234567890123456789012345678901234567890

-----------------------------------------------------------------------

IIIIIIIIIIIIIIIIIIIIIIIIIIIIII HDOB NN YYYYMMDD

AF302 1712A KATRINA HDOB 41 20050928  example

III...III: Mission identifier, as determined in Chapter 5, paragraph 5.7.7.

NN: Observation number (01-99), assigned sequentially for each HDOB 

message during the flight. This sequencing is independent of the 

numbering of other types of messages (RECCO, DROP, VORTEX, 

etc.), which have their own numbering sequence.

YYYYMMDD: Year, month, and day of the first HD/HA data line of the message.
G-11

Table G-6. HD/HA Data Line Format for HDOB Messages

0 1 2 3 4 5 6 7

01234567890123456789012345678901234567890123456789012345678901234567890

-----------------------------------------------------------------------

hhmmss LLLLH NNNNNH PPPP GGGGG XXXX sTTT sddd wwwSSS MMM KKK ppp FF

142230 2612N 08752W 7010 03057 9282 +102 +102 141153 166 148 /// 00

hhmmss: Observation time, in hours, minutes and seconds (UTC). The 

observation time is the midpoint of the 30-s averaging interval used for 

the record’s meteorological data.

LLLLH: The latitude of the aircraft at the observation time in degrees (LL) and 

minutes (LL). The hemisphere (H) is given as either N or S.

NNNNNH: The longitude of the aircraft at the observation time, in degrees (NNN) 

and minutes (NN). The hemisphere (H) is given as either E or W.

PPPP: Aircraft static air pressure, in tenths of mb with decimal omitted, at the 

observation time. If pressure is equal to or greater than 1000 mb the 

leading 1 is dropped. 

GGGGG: Aircraft geopotential height, in meters, at the observation time. 

‘////’indicates missing value.

XXXX: Extrapolated surface pressure or D-value (30-s average). Encoded as 

extrapolated surface pressure if aircraft static pressure is 550.0 mb or 

greater (i.e., flight altitudes at or below 550 mb). Format for 

extrapolated surface pressure is the same as for static pressure. For 

flight altitudes higher than 550 mb, XXXX is encoded as the D-value, 

in meters. Negative D-values are encoded by adding 5000 to the 

absolute value of the D-value. /// indicates missing value.

s: Sign of the temperature or dew point (+ or -).

sTTT: The air temperature in degrees and tenths Celsius, decimal omitted (30-

s average). //// indicates missing value.

sddd: The dew point temperature, in degrees and tenths Celsius, decimal 

omitted (30-s average). //// indicates missing value.

www: Wind direction in degrees (30-s average). North winds are coded as 

000. /// indicates missing value.

SSS: Wind speed, in kt (30-s average). /// indicates missing value.
G-12

MMM: Peak 10-second average wind speed occurring within the encoding 

interval, in kt. /// indicates missing value.

KKK: Peak 10-second average surface wind speed occurring within the 

encoding interval from the Stepped Frequency Microwave Radiometer 

(SFMR), in kt. /// indicates missing value.

ppp: SFMR-derived rain rate, in mm hr-1, evaluated over the 10-s interval 

chosen for KKK. /// indicates missing value.

FF: Quality control flags.

First column indicates status of positional variables as follows: 

 0 All parameters of nominal accuracy

 1 Lat/lon questionable

2 Geopotential altitude or static pressure questionable

 3 Both lat/lon and GA/PS questionable

Second column indicates status of meteorological variables as follows:

0 All parameters of nominal accuracy 

1 T or TD questionable

2 Flight-level winds questionable

3 SFMR parameter(s) questionable

4 T/TD and FL winds questionable

5 T/TD and SFMR questionable

6 FL winds and SFMR questionable

9 T/TD, FL winds, and SFMR questionable
G-13

G.2.3. TEMP DROP.

The TEMP DROP code message provides a representation of quality-controlled vertical 

measurements of pressure, temperature, moisture, and winds acquired from dropsondes released 

from reconnaissance aircraft. The message consists primarily of two main sections: Part A and 

B. In Part A, temperature, dew point depression, and wind measurements are reported at the 

surface and at every mandatory pressure level the dropsonde traverses as it descends from flight 

level. A hydrostatically-computed seal-level pressure obtained from sonde data is reported with 

the surface data. Calculated geopotential heights based on upward or downward hydrostatic 

integration of the sonde data are also reported with the mandatory pressure levels. In Part B, 

thermodynamic (temperature and dew point depressions) and wind measurements are reported at 

significant pressure levels traversed by the dropsonde from flight level to the surface. The 

significant levels are selected from a quality-control algorithm where local extrema occur in the 

vertical profiles of the thermodynamic and wind data and at other set criteria. Additional 

information is provided in remarks lines at the end of each section, including but not limited to 

aircraft mission ID, observation number, and dropsonde release and splash times and locations. 

If the dropsonde is released by an aircraft at a pressure altitude above 100 mb, the TEMP DROP 

message will contain additional Parts C and D, which are analogous to Parts A and B, for 

mandatory and significant level measurements < 100 mb.

Sample USAFR/53 WRS and NOAA TEMP DROP messages are shown in Figure G-5. A 

detailed explanation of each element within a TEMP DROP message is presented in Table G-7. 
G-14

Figure G-5. Example TEMP DROP Message for Tropical Cyclones

UZNT13 KNHC 142311

XXAA 64237 99217 70659 07915 99980 26006 06101 00678 ///// /////

92510 22606 09596 85247 20034 11595 70897 09802 15605 88999 77999

31313 09608 82244

61616 AF302 0608A GONZALO OB 10

62626 EYEWALL 045 MBL WND 08107 AEV 07775 DLM WND 11593 980697 WL

150 07105 083 REL 2167N06592W 224447 SPG 2173N06603W 224927 =

XXBB 64238 99217 70659 07915 00980 26006 11910 21808 22888 22644

33850 20034 44787 15207 55712 12008 66697 09200

21212 00980 06101 11977 06598 22973 06605 33967 07107 44961 08617

55953 08621 66947 08610 77944 08613 88939 09103 99932 09603 11926

09596 22910 10101 33901 10594 44894 10599 55850 11595 66697 15605

31313 09608 82244

61616 AF302 0608A GONZALO OB 10

62626 EYEWALL 045 MBL WND 08107 AEV 07775 DLM WND 11593 980697 WL

150 07105 083 REL 2167N06592W 224447 SPG 2173N06603W 224927 =

UZNT13 KWBC 022227

XXAA 52221 99312 70715 11611 99020 27647 19010 00175 26037 18510

92859 21858 20007 85587 17459 17508 70224 10883 24008 50593 08549

28509 40762 19161 33506 30970 33964 17507 25095 43970 24007 20241

56165 21008 15419 679// 30013 88999 77999

31313 09608 82202

61616 NOAA9 0701A ARTHUR OB 20

62626 MBL WND 18510 AEV 07725 DLM WND 23505 019148 WL150 18510 08

2 REL 3119N07150W 220214 SPG 3120N07148W 221846 =

XXBB 52228 99312 70715 11611 00020 27647 11969 23829 22958 24261

33935 22457 44891 19661 55883 19050 66869 18460 77855 17656 88850

17459 99838 16862 11807 14856 22794 14461 33789 14259 44781 14264

55702 11083 66670 07867 77648 06283 88601 01868 99573 00778 11559

01970 22546 03562 33525 06361 44515 07323 55494 09356 66453 13928

77416 17163 88411 17759 99405 18561 11363 24357 22355 25363 33343

27159 44328 28767 55313 31563 66286 36371 77190 58765 88148 683//

21212 00020 19010 11965 19010 22895 20003 33850 17508 44661 25010

55643 24010 66448 35010 77324 19511 88187 32513 99162 29514 11154

33017 22148 28513

31313 09608 82202

61616 NOAA9 0701A ARTHUR OB 20

62626 MBL WND 18510 AEV 07725 DLM WND 23505 019148 WL150 18510 08

2 REL 3119N07150W 220214 SPG 3120N07148W 221846 =
G-15

Table G-7. TEMP DROP CODE

EXTRACT FROM: WMO-No. 306 MANUAL ON CODES

FM 37-X Ext. TEMP DROP: Upper-level pressure, temperature, humidity and wind report from a sonde released by 

carrier balloons or aircraft. See Figure G-5 for an example TEMP DROP message for tropical cyclone operations.

CODE FORM:

PART A

SECTION 1 MiMiMjMj YYGGId 99LaLaLa QcLoLoLoLo MMMULaULo

SECTION 2 99PoPoPo ToToTaoDoDo dodofofofo

P1P1h1h1h1 T1T1Ta1D1D1 d1d1f1f1f1

PnPnhnhnhn TnTnTanDnDn dndnfnfnfn

SECTION 3 88PtPtPt TtTtTatDtDt dtdtftftft

or

88999

SECTION 4 77PmPmPm dmdmfmfmfm (4vbvbvava)

or

66PmPmPm dmdmfmfmfm (4vbvbvava)

or

77999

SECTION 10 31313

51515 101Adf Adf 0PnPnP'nP'n.

or

101Adf Adf PnPnhnhnhn 

61616

62626

PART B

SECTION 1 MiMiMjMj YYGG8 99LaLaLa QcLoLoLo MMMULaULo

SECTION 5 nonoPoPoPo ToToTaoDoDo

n1n1P1P1P1 T1T1Ta1D1D1

nnnnPnPnPn TnTnTanDnDn

SECTION 6 21212 nonoPoPoPo dodofofofo
G-16

n1n1P1P1P1 d1d1f1f1f1

nnnnPnPnPn dndnfnfnfn

SECTION 7 31313 srrarasasa 8GGgg

SECTION 9 51515 101Adf Adf or

101Adf Adf 0PnPnP'nP'n. or

101Adf Adf PnPnhnhnhn 

SECTION 10 61616

62626

PART ALPHA (A)

IDENTIFICATION LETTERS: MJMJ

Identifier: MJMJ - Identifier for Part A of the report.

DATE/TIME GROUP: YYGGId

Identifier: YY - Date group

Identifier: GG - Time group

Identifier: Id - The highest mandatory level for which wind is available.

LATTITUDE: 99LaLaLa

Identifier: 99 – Indicator for data on position follows.

Identifier: LaLaLa – Latitude in tenths of degrees

LONGITUDE: QcLoLoLoLo

Identifier: Qc – The octant of the globe.

Identifier: LoLoLoLo – Longitude in tenths of degrees

MARSDEN SQUARE: MMMUlaUlo

Identifier: MMM - Marsden square"(see Figure G-6 for geographical depiction) . 

Identifier: UlaUlo – Units digits in the reported latitude and longitude.

SEA LEVEL PRESSURE: 99P0P0P0 T0T0T0D0D0 d0d0f0f0f0

Identifier: 99 – Indicator for data at the surface level follows

Identifier: P0P0P0 – Indicator for pressure of specified levels in whole millibars (thousands digit omitted) 

Identifier: T0T0T0– Tens and digits of air temperature (not rounded off) in degrees Celsius, at specified levels 

beginning with surface.

Identifier: D0D0 – Dewpoint depression at standard isobaric surfaces beginning with surface level. 

NOTE

When the depression is 4.9C or less encode the units and tenths digits of the depression. Encode 

depressions of 5.0 through 5.4C as 50. Encode depressions of 5.5C through 5.9C as 56. Dew point 

depressions of 6.0 and above are encoded in tens and units with 50 added. Dew point depressions 
G-17

for relative humidities less then 20% are encoded as 80. When air temperature is below –40C 

report DnDn as //.

Identifier: dodo – True direction from which wind is blowing rounded to nearest 5 degrees. Report hundreds and tens 

digits. The unit digit (0 or 5) is added to the hundreds digit of wind speed.

Identifier: fofofo – Wind speed in knots. Hundreds digit is sum of speed and unit digit of direction, i.e. 295o at 125 

knots encoded as 29625. 

NOTE: 1. When flight level is just above a standard surface and in the operator’s best meteorological judgment, the 

winds are representative of the winds at the standard surface, then the operator may encode the standard surface 

winds using the data from flight level. If the winds are not representative, then encode /////.

NOTE: 2. The wind group relating to the surface level (dodofofofo) will be included in the report; when the 

corresponding wind data are not available, the group will be encoded as /////. 

STANDARD ISOBARIC SURFACES : P1P1h1h1h1 T1T1T1D1D1 d1d1f1f1f1

Identifier: P1P1 – Pressure of standard isobaric surfaces in units of tens of millibars.

(1000 mbs = 00, 925mbs = 92, 850mbs = 85, 700mbs = 70, 500mbs = 50, 400mbs = 40, 300mbs = 30, 

250mbs = 25).

Identifier: h1h1h1 – Heights of the standard pressure level in geopotential meters or decameters above the 

surface. Encoded in decameters at and above 500mbs omitting, if necessary, the thousands or tens of 

thousands digits. Add 500 to the absolute value of hhh for negative 1000mb or 925mb heights. Report 

1000mb group as 00/// ///// ///// when pressure is less than 950mbs.

Identifier: T1T1T1D1D1 – Same temperature/dew point encoding procedures apply to all levels.

Identifier : d1d1f1f1f1 – Same wind encoding procedures apply to all levels.

DATA FOR TROPOPAUSE LEVELS: 88 PtPtPt TtTtTtDtDt dtdtftftft

Identifier: 88 – Indicator for Tropopause level follows

Identifier: PtPtPt– Pressure at the tropopause level reported in whole millibars. Report 88PnPnPn as 88999 when 

tropopause is not observed.

Identifier: TtTtTtDtDt – Same temperature/ dew point encoding procedures apply.

Identifier: dtdtftftft - Same wind encoding procedures apply.

MAXIMUM WIND DATA: 77PnPnPn dndnfnfnfn 4vbvbvava

Identifier: 77 – Indicator that data for maximum wind level and for vertical wind shear follow when max wind does 

not coincide at flight. If the maximum wind level coincides with flight level encode as 66. Report 77PnPnPn as 

77999 when maximum wind data has not been observed.

Identifier: PnPnPn.– Pressure at maximum wind level in whole millibars.

Identifier: dndnfnfnfn - Same wind encoding procedures apply.

VERTICAL WIND SHEAR DATA: 4vbvbvava

Identifier: 4 – Data for vertical wind shear follow.

Identifier: vbvb – Absolute value of vector difference between max wind and wind 3000 feet BELOW the level of 

max wind, reported to the nearest knot. Use “//” if missing and a 4 is reported. A vector difference of 99 knots 

or more is reported with the code figure “99”.

Identifier: vava – Absolute value of vector difference between max wind and wind 3000 feet above the level of max 

wind, reported to the nearest knot. Use “//” if missing and a 4 is reported. A vector difference of 99 knots or 

more is reported with the code figure “99”.
G-18

SOUNDING SYSTEM INDICATION, RADIOSONDE/ SYSTEM STATUS, LAUNCH TIME:

31313 srrarasasa 8GGgg

Identifier: srrarasasa - Sounding system indicator, radiosonde/ system status: sararasasa

Identifier: sa - Solar and infrared radiation correction ( 0 – no correction)

Identifier: rara – Radiosonde/sounding system used ( 96 – Descending radiosonde)

Identifier: sasa – Tracking technique/status of system used ( 08 – Automatic satellite navigation)

Identifier: 8GGgg – Launch time

Identifier: 8 – Indicator group

Identifier: GG – Time in hours

Identifier: gg – Time in minutes 

ADDITIONAL DATA GROUPS: 51515 101XX 0PnPnPnPn

Identifier: 51515 – Additional data in regional code follow

Identifier: 10166 – Geopotential data are doubtful between the following levels 0PnPnPnPn. This code figure is used 

only when geopotential data are doubtful from one level to another. 

Identifier: 10167 – Temperature data are doubtful between the following levels 0PnPnPnPn. This code figure shall be 

reported when only the temperature data are doubtful for a portion of the descent. If a 10167 group is reported a 

10166 will also be reported. EXAMPLE: Temperature is doubtful from 540mbs to 510mbs. SLP is 1020mbs. 

The additional data groups would be : 51515 10166 00251 10167 05451. 

Identifier: 10190 – Extrapolated altitude data follows:

When the sounding begins within 25mbs below a standard surface, the height of the surface is reported in 

the format 10190 PnPnhnhnhn. The temperature group is not reported. EXAMPLE: Assume the 

release was made from 310mbs and the 300mb height was 966 decameters. The last reported 

standard level in Part A is the 400mb level. The data for the 300mb level is reported in Part A and B 

as 10190 30966.

When the sounding does not reach surface, but terminates within 25mbs of a standard surface, the height 

of the standard surface is reported in Part A of the code in standard format and also at the end of Part 

A and Part B of the code in the format as 10190 PnPnhnhnhn.

EXAMPLE: Assume termination occurred at 980mbs and the extrapolated height of the 1000mb 

level was 115 meters. The 1000mb level would be reported in Part A of the code as 00115 ///// ///// 

and in Part B as 10190 00115.

Identifier: 10191 – Extrapolated surface pressure precedes. Extrapolated surface pressure is only reported when the 

termination occurs between 850mbs and the surface. Surface pressure is reported in Part A as 99P0P0P0 ///// and in 

Part B as 00P0P0P0 /////. When surface pressure is extrapolated the 10191 group is the last additional data group 

reported in Part B.

AIRCRAFT AND MISSION IDENTIFICATION: 61616 AFXXX XXXXX XXXXX OB X

Identifier: 61616 – Aircraft and mission identification data follows.

Identifier: AFXXX – The identifier AF for U.S. Air Force and the last three digits of the aircraft’s tail number.

Identifier: XXXXX XXXXX – The identifier for the type of mission being flown.

If a training mission the mission identifier is WXWXA TRAIN. The fifth letter “A” is the only character 

that could possibly change. The “A” indicates that the flight originated in the Atlantic basin. The 

letter “C” identifies the Central Pacific area, the letter “E” identifies the Eastern Pacific, and the 

letter “W” identifies the Western Pacific.

If an operational storm mission: the first two numbers Identifier the number of times an aircraft has flown 

this system and the second two numbers Identifier the system number. The last character again 

identifies the basin flown. The name of the storm would replace TRAIN.

EXAMPLE: AF968 0204A MARIE – Aircraft number 50968, this was the second flight into this 

system and the system was the fourth of the season. The system reached tropical storm strength and 

was named MARIE.

Identifier: OB 14 – The observation (both vertical and horizontal) number as transmitted from the aircraft.
G-19

NATIONALLY DEVELOPED CODES: 62626

Identifier: 62626 – This is the remarks section. Only the remarks CENTER, EYEWALL XXX, MXWNDBND, or 

RAINBAND will be used. If the remark EYEWALL is used it will be followed by the octant (degrees) sonde is 

located relative to eye center. Example: If the sonde is released in the NE quad of the storm, XXX is 045.

Identifier: REL XXXXNXXXXXW hhmmss - the time and location of the highest (in altitude) wind reported in the 

temp drop message

Identifier: SPG XXXXNXXXXXW hhmmss - the time and location of the lowest (in altitude) wind reported in the 

temp drop message.

Identifier: SPL XXXXNXXXXXW hhmm - Impact location of the sonde based on its last GPS position and the 

splash time. (SPL has less precision than SPG and is now obsolete).

Identifier: LAST WND XXX - Height of the last reported wind. If a surface wind is reported the Last Wind remark 

is omitted. XXX will never be less than 13 meters

Identifier: MBL WND dddff - The mean boundary level wind. The mean wind in the lowest 500 meters of the 

sounding

Identifier: AEV XXXXX - This is the software version being used for the sounding. 

Identifier: DLM WND ddfff bbbttt - The Deep Layer Mean wind. It is the average wind over the depth of the 

sounding. Where ddfff is the wind averaged from the first to the last available wind (these would correspond to 

the first and last significant levels for wind); ttt is the pressure at the top of the layer, and bbb is the pressure at 

the bottom of the layer (in whole mbs, with thousands digit omitted). 

Identifier: WL150 ddfff zzz - Average wind over the lowest available 150 m of the wind sounding. Where ddfff is 

the mean wind over the 150 m layer centered at zzz m.

PART ALPHA (B)

DATA FOR SIGNIFICANT TEMPERATURE AND RELATIVE HUMIDITY LEVELSSIGNIFICANT 

ISOBARIC LEVELS:

n0n0P0P0P0 T0T0T0D0D0

IDENTIFICATION LETTERS: MJMJ

Identifier: MJMJ - Identifier for Part B of the report.

DATE/TIME GROUP: YYGG8 

Identifier: YY - Date group

Identifier: GG - Time group

Identifier: 8 - Indicator for the use of satellite navigation for windfinding.

LATTITUDE: 99LaLaLa (Same as Part A)

LONGITUDE: QcLoLoLoLo (Same as Part A)

MARSDEN SQUARE: MMMUlaUlo (Same as Part A)

SEA LEVEL PRESSURE: nonoP0P0P0 T0T0T0D0D0

Identifier: nono – Indicator for number of level starting with surface level. Only surface will be numbered as “00”.

Identifier: P0P0P0 – Indicator for pressure of specified levels in whole millibars (thousands digit omitted) 

Identifier: T0T0T0– Tens and digits of air temperature (not rounded off) in degrees Celsius, at specified levels 

beginning with surface.

Identifier: D0D0 – Dewpoint depression at standard isobaric surfaces beginning with surface level. Encoded the same 

as Part A.

FOR STORM DROPS ONLY. If SLP is less than 950mb encode the 1000mb group as 00/// ///// /////. When the 

SLP is between 950mb and 999mb encode 1000mb as 00PoPoPo ///// ///// (500 meters are added to height below 

surface).
G-20

DATA FOR SIGNIFICANT WIND LEVELS: n0n0P0P0P0 dodofofofo

Identifier: n0n0 – Number of level starting with surface level. Only surface will be numbered as “00”. 

Identifier: P0P0P0 – Pressure at specified levels in whole millibars.

Identifier: dodo – True direction from which wind is blowing rounded to nearest 5 degrees. Report hundreds and tens 

digits. The unit digit (0 or 5) is added to the hundreds digit of wind speed.

Identifier: fofofo – Wind speed in knots. Hundreds digit is sum of speed and unit digit of direction, i.e. 295o at 125 

knots encoded as 29625. 

Same notes in Part A apply.

31313, 51515, 61616, 62626 – Repeated from Part A.

Figure G-6. Marsden Square Reference Diagram
I-1

APPENDIX I: TELEPHONE LISTING

AGENCY LOCATION TELEPHONE

Department of Commerce

NHC

 Director

 Atlantic Forecast Operations

 Pacific Forecast Operations

 Admin

 Admin Fax

 TAFB Pacific/Classification Desk

Miami, FL

COM 305-229-4402

COM 305-229-4415

COM 305-229-4417

COM 305-229-4470

FAX 305-553-1901

COM 305-229-4425

CPHC

 Director

 Forecaster and Warning Desk

 Admin

 Operations

 Satellite Coordinator

Honolulu, HI

COM 808-973-5272

COM 808-973-5284

COM 808-973-5270

FAX 808-973-5281

COM 808-973-5285

NOAA Aircraft Operations Center MacDill AFB, FL COM 813-828-3310

NCEP/NCO Senior Duty Met (Data QC) College Park, MD COM 301-683-1500

Weather Prediction Center (NCEP/WPC) College Park, MD COM 301-683-1530

NESDIS Satellite Analysis Branch College Park, MD COM 301-683-1400

WFO Guam Tiyan, Guam COM 671-472-0950/1/2

NDBC - Operations Branch Stennis Space Center, MS COM 228-688-7720

NWS National Operations Center (Headquarters) Silver Spring, MD COM 301-244-9650

Interdepartmental

OFCM Silver Spring, MD COM 301-628-0112

Department of Defense

JTWC (Typhoon Duty Officer) Pearl Harbor, HI COM 808-474-2320

53rd Weather Reconnaissance Squadron (WRS)

 Supervisor of Flights

 Chief ARWO

 Alternate CARCAH

53 WRS

817 H Street, Suite 201

Keesler AFB, MS 39534-2453

DSN 597-2409

COM 228-377-2409

DSN 597-3207

COM 228-377-3207

DSN 597-9060

COM 228-377-9060

CARCAH OLA, 53d WRS Miami, FL COM 305-229-4474

DSN 434-3420

Keesler AFB Command Post Keesler AFB, MS COM 228-377-4181/4330

DSN 597-4181/4330

557th Weather Wing (557 WW) Offutt AFB, NE COM 402-294-2586

DSN 271-2586

FACSFAC VACAPES OAC Oceana, VA COM 804-433-1233

DSN 433-1233

17 OWS/WXJ (Satellite Analyst) Pearl Harbor, HI COM 787-865-7007

DSN 471-3533

601 AOC/CODW Tyndall AFB, FL COM 850-283-5119

DSN 523-5119

Fleet Weather Center Norfolk, VA COM 757-444-7583/7750

DSN 564-7583/7750

Fleet Numerical Meteorology & Oceanography 

Center (FNMOC) (Alternate JTWC) Monterey, CA COM 831-656-4325DSN 878-4325

TMC – Traffic Management Coordinator

OMIC - Operations Manager in Charge

STMC – Supervisor Traffic Management Coordinator
I-2

Department of Transportation

Air Route Traffic Control Center (ARTCC)

Air Traffic Control System Command Center (ATCSCC)

ARTCC Facility 

ID

Primary 

Operations 

Contact Point

Secondary 

Operations 

Contact Point

(24 hour number)

Operations 

Fax Number

Center

Weather 

Service Unit 

(CWSU)

ANCHORAGE ZAN 907-269-1103

(OMIC)

907-269-1108

(TMC) 907-269-1343 907-269-1145

BOSTON ZBW 603-879-6663

(TMC)

603-879-6655 

(OMIC) 603-879-6461 603-879-6698

HOUSTON ZHU 281-230-5563 

(Missions)

281-230-5560

(OMIC) 281-230-5561 281-230-5676

JACKSONVILLE ZJX 904-549845-1542 

(Missions)

904-549845-1537

(OMIC)

904-549845-

1843

904-549845-

1840 or 904-

549845-1839

LOS ANGELES ZLA 661-265-8287 

(Missions)

661-265-8205

(OMIC) 661-265-8277 661-265-8258

MIAMI ZMA 305-716-1589 

(Missions)

305-716-1588

(OMIC)

305-716-1511 

or 305-716-

1577

305-716-1635

NEW YORK ZNY 631-468-1427 

(Missions)

631-468-1080

(STMC) 631-468-4224 631-468-1082

OAKLAND ZOA 510-745-3332 

(Missions)

510-745-3331

(OMIC) 510-745-3339 510-745-3425

SEATTLE ZSE 253-351-3523 

(Missions)

253-351-3520 

(OMIC)

253-351-3594 

or 253-351-

3538

253-351-3741

WASHINGTON ZDC 703-771-3473 

(Missions)

703-771-3470 

(OMIC) 703-771-3444 703-771-3480

HONOLULU 

HCF ZHN 808-840-6204(TMC)

808-840-6201

(Front Line Manager) 808-840-6210 N/A

SAN JUAN 

CERAP ZSU

787-253-8665 

(Front Line 

Manager)

787-253-8664

(Front Line Manager) 787-253-8650 N/A

GUAM CERAP ZUA

671-473-1210 

(Front Line 

Manager)

671-473-1270

(Missions) 671-473-1217 N/A

OFFICE TELEPHONE

MANAGER, ATCSCC COM 540-422-4004

PRIMARY OPERATIONS CONTACT POINT

INTERNATIONAL OPERATIONS POSITION

COM 540-422-4158

FAX 540-422-4196

SECONDARY OPERATIONS CONTACT POINT

NATIONAL OPERATIONS MANAGER (NOM)

COM 540-422-4100/4101/4102

 800-333-4286 (Military Use Only)

FAX 540-422-4196

CENTRAL ALTITUDE RESERVATION 

FUNCTION (CARF)

COM 540-422-4211/4212

FAX 540-422-4291

US NOTAM Office COM 540-422-4260/4261

FAX 540-422-4983

DoD Air Traffic Services Cell COM 540-422-4250

DSN 510-422-4250
I-3

Transport Canada (ANS Regulatory Authority)

Civil Aviation Contingency Operations (CACO) Office COM (Toll-free from Canada) 1-877-992-6853

FAX (Toll-free from Canada) 1-866-993-7768

NAV CANADA (ANS Provider)

National Operations Centre (NOC)

OFFICE TELEPHONE

Admin Hours 0600-2200 (local Eastern time)

NOC (24 Hours) (ATCSCC of Canada)

COM 613-563-5626

COM 613-563-5667

COM (Toll-free from Canada) 1-866-561-9053

COM (Toll-free from U.S.A.) 1-866-651-9056

FAX 613-563-3481

International NOTAM Office (Canada) COM 613-248-4000

FAX 613-248-4001

Altitude Reservation Units (ARU)

OFFICE TELEPHONE

ARU West (Edmonton ACC) (responsible for 

Vancouver, Edmonton and Winnipeg FIRs)

COM 780-890-4739 

FAX 780-890-4738

ARU East (Gander ACC) (responsible for Toronto, 

Montreal, Moncton and Gander FIRs)

COM 709-651-5243

FAX 709-651-5288

Area Control Centers (ACC)

ACC Facility ID

Primary 

Operations 

Contact Point

(Shift Manager)

Secondary 

Operations 

Contact Point

Fax Number

TORONTO ZYZ 905-676-4509 905-676-4562 905-612-5613

MONTREAL ZUL 514-633-3365 514-633-2871 514-633-3371

MONCTON ZOM 506-867-7173 506-381-4684 506-867-7180

WINNIPEG ZWG 204-983-8338 204-983-8483 204-984-0030

EDMONTON ZEG 780-890-8397 780-890-8323 780-890-8011

GANDER ZQX 709-651-5207 709-651-5223 709-651-5234

VANCOUVER ZVR 604-598-4500 604-598-4850 604-586-4502
I-4
J-1

APPENDIX J: GEOGRAPHICAL DEFINING POINTS 

AND PHONETIC PRONUNCIATIONS

Abaco AB-a-KO

Abreojos aahbray-oh-hoes

Amalie a-MAHL-ye

Angel aan-hel

Anguilla ang-GWIL-a

Antigua an-TEE-ga

Arena aah-ray-nah

Arista ah-ree-staa

Aruba ah-ROO-ba

Antilles an-TILL-leez

Azores uh-ZOHRZ

Bahia ba-e-yuh

Ballenas ba-yaynas

Barahona ba-ra-HO-na

Barbados bar-BAY-dohz

Barbuda bar-BOO-dah

Barra baa-rra

Barranquilla Bahr-rahn-KEE-yah

Basse-Terre baha-TER

Bimini BIM-I-ni

Bonaire ba-NAIR

Burros bhoorroes

Cap Haitien kahp ah-ee-SYAN

Caracas kah-RAH-kahs

Cardenas car-denaass

Caribbean kar-a-BE-an

Castries KAS-tree

Cayman kay-MAHN

Champerico chaam-per-e-coe

Charlotte SHAR-luht

Colima coleema

Corrientes cor-re-ehn-tays

Cozumel koh-soo-MEL

Curacao koor-a-SOH

Cuyutlan coo-yootlaan

Dominica dom-I-NEE-ka

Eleuthera el-OO-thera

Escondido es-cond-dee-dow

Eugenia ayuh-hen-yuh

Exuma ek-SOO-ma

Flores FLO-rish

Fort de France for-de-FRAHCS

Galera gaa-lehra

Grenada gre-NAY-dah

Guadaloupe GWAH-deh-loop

Guasave gwaa-saa-ve

Guaymas gwhy-maahs

Huatulco whaa-tool-coe

Islas eeslas

Jalisco ha-lee-sco

Juanico whaa-nee-coe

Lazaro laasa-roe

Loreto lo-ae-toe

Leeward LEE-werd

Manzanillo manza-nee-oh

Maracaibo mar-a-KYE-boh

Maracay mah-rah-KYE

Marigot ma-ree-GOH

Mateo muh-ta-yo

Mayaguez may-yah-GWAYS

Medano may-daa-no

Melaque may-laa-kay

Merida MAY-re-thah

Mochis mo-chees

Montego mon-TEE-go

Montserrat mont-se-RAT

Mugu muhgu

Mulege moo-lay-hay

Nicaragua nik-a-RAH-gwah
J-2

Ocho Rios OH-cho REE-os

Oranjestad o-RAHN-yuh-stat

Paramaribo par-a-MAR-I-boh

Parguera par-GWER-a

Penasco pen-yaas-co

Pointe-a-Pitre pwan-ta-PEE-tr

Ponce PON-sa

Port-au-Prince port-oh-PRINS

Punta poonta

Revillagigedo ray-veeaheehaydo

Saba SAH-ba

Sao Miguel soun ME-gel

Sipacate see-paa-caa-tay

St Croix ST croy

St Lucia ST LOO-she-a

Soufriere soo-free-AR

Surinam SOOR-I-nam

Tampico tam-PEE-ko

Tehuantepec te-whaan-te-pec

Tela TAY-lah

Tobago to-BAY-go

Todos todohs

Tomas tow-maas

Tonala ton-aahla

Tosca toesca

Vallarta vah-yar-ta

Yavaros yaa-vaa-roce

Yucatan yoo-ka-TAN

Zihuatanejo zeeh-whaa-tanay-ho
K-1 

APPENDIX K: NHOP OPERATIONAL MAPS

(TERMINAL AREAS)

Figure K-1. Texas Coast
K-2 

Figure K-2. Lake Charles, LA - Pensacola, FL
K-3 

Figure K-3. Pensacola, FL – Tallahassee, FL
K-4 

Figure K-4. Central/Southern Florida
K-5 

Figure K-5. Cuba – Grand Cayman
K-6 

Figure K-6. The Bahamas: Nassau - Freeport
K-7 

Figure K-7. Turks & Caicos Islands: Grand Turk - Providenciales
K-8 

Figure K-8. Daytona Beach, FL – Myrtle Beach, SC
K-9 

Figure K-9. Wilmington, DE – Atlantic City, NJ
K-10

Figure K-10. Radar coverage map – San Juan, PR, Air Route Traffic Control Center. Radar range 

rings based on line-of-sight shown in color. 
K-11

Figure K-11. Radar coverage map – Miami, FL, Air Route Traffic Control Center. 

Radar range rings based on line-of-sight shown in color
K-12
53d WRS OPS: (228) 377-2409 NOAA OPS: (813) 828-4338 DATE: 

APPENDIX L: 53d WRS/NOAA MISSION COORDINATION 

SHEET

1. Aircraft Call Sign: 

2. TCPOD Number: 

3. Departure Airfield: 

4. Route of Flight: 

PARTICIPATING AIRCRAFT REQUESTS AN FDC NOTAM FOR WRA ___________

BE SET / SHIFTED WITH THE FOLLOWING INFORMATION:

5. Delay/WRA Center Coordinates: 

6. Radius of Operation from Center Coordinates: 200 NM

7. Valid Time for WRA: 

8. Requested Block Altitude: SFC – 15000’ MSL

9. Name of Storm:

10. Aircraft Tail #: 

11. SATPHONE: GRND to AIRCRAFT ______________________________

AIRCRAFT to AIRCRAFT ______________________________

12. HF Selcal (if applicable): 

13. Requested NORAD Transponder Code: 

FAX TO THE ARTCCs AND ATCSCC ASAP PRIOR TO DEPARTURE TIME. 

IF WRA IMPACTS WARNING AREAS, CONTACT APPROPRIATE MILITARY 

CONTROL FACILITY. I.E. GIANT KILLER OR SEALORD

_____ ATCSCC PRI OPS CONTACT (INT’L OPS) FAX 540-422-4196 VOICE: 540-422-4100

_____ HOUSTON (ZHU) FAX: 281-230-5561 VOICE: 281-230-5563 DSN 885-1491

_____ JAXVILLE (ZJX) FAX: 904-845-1843 VOICE: 904-845-1542/1543/1546 (Atlantic) DSN 434-3744

_____ MIAMI (ZMA) FAX: 305-716-1511/1577 VOICE: 305-716-1588/1589 DSN 434-1910

_____ WASHINGTON (ZDC) FAX: 703-771-3444 VOICE: 703-771-3470 OPT 1

_____ NEW YORK (KZNY) FAX: 631-468-4224 VOICE: 631-468-1427/1080 DSN 881-3730

_____ GIANT KILLER (Vacapes, VA) / DSN 433-1218/1220 COMM 757-433-1218/1220

_____ SEALORD (Jacksonville, FL) / DSN 942-2250 / COMM 904-542-2250
L-2
M-1

APPENDIX M: ACRONYMS/ABBREVIATIONS 

-AAB Data type header for Tropical Weather Outlook 

AFB Air Force Base 

AFRC Air Force Reserve Command 

AFSATCOM Air Force Satellite Communications System 

AFWA Air Force Weather Agency 

AGL Above Ground Level

AHI Advanced Himawari Imager

AMSR2 Advanced Microwave Scanning Radiometer 2

AMSU Advanced Microwave Sounding Unit 

AOC Aircraft Operations Center (NOAA) 

APT Automatic Picture Transmission

ARGOS Argos, Inc., a French data collection system 

ARINC Aeronautical Radio, Incorporated

ARSA Airport Radar Service Area 

ARTCC Air Route Traffic Control Center 

ARWO Aerial Reconnaissance Weather Officer 

ASCAT Advanced Scatterometer

ATC Air Traffic Control 

ATCSCC Air Traffic Control System Command Center 

ATMS Advanced Technology Microwave Sounder

ATSC Air Traffic Services Cell (DoD; Hq USAF/A3OP)

AVAPS Advanced Vertical Atmospheric Profiling System 

AVHRR Advanced Very High Resolution Radiometer 

AWIPS Advanced Weather Interactive Processing System

AXBT Airborne Expendable Bathythermograph

-BbTPW Blended Total Precipitable Water

BUFR Binary Universal Format

-CCARCAH Chief, Aerial Reconnaissance Coordination, All Hurricanes 

CARF Central Altitude Reservation Function 

CDA Command and Data Acquisition

CERAP Combined Center RAPCON (FAA) 

CFW Coastal/Lakeshore Hazard Message products (AWIPS 

Product Category CFW)

C.I. Current Intensity 

C-MAN Coastal-Marine Automated Network 

CNMI Commonwealth of the Northern Mariana Islands 
M-2

COM Commercial (telephone) 

COMS Communication, Ocean and Meteorology Satellite

CONUS Continental United States 

CPHC Central Pacific Hurricane Center 

-DDA Daylight Ascending 

deg degree (latitude or longitude) 

DMSP Defense Meteorological Satellite Program 

DOC Department of Commerce 

DOD Department of Defense

DOMSAT domestic satellite

DOT Department of Transportation 

DPTD departed 

DROP dropsonde/dropwindsonde 

DSN Defense Switched Network (formerly AUTOVON)

-EEOS (NASA) Earth Observing System

ESA European Space Agency 

ESPC Environmental Satellite Processing Center

ETA Estimated Time of Arrival

eTRaP Ensemble Tropical Rainfall Potential

-FFAA Federal Aviation Administration 

FACSFAC Fleet Aerial Control and Surveillance Facility 

FCMSSR Federal Committee for Meteorological Services and 

Supporting Research

FCST forecast 

FCSTR forecaster 

FEA Flow Evaluation Area (FAA) 

FL flight level 

FLT LVL flight level 

FMH Federal Meteorological Handbook 

FNMOC Fleet Numerical Meteorology and Oceanography Center 

USN) 

FSM Federated States of Micronesia 

ft foot/feet 

-GGAASP GCOM-W1 AMSR2 Algorithm Software Package

GAC Global Area Coverage 

GCOM Global Change Observation Mission
M-3

GLM Geostationary Lightning Mapper

GMI GPM microwave imager

GMDSS Global Maritime Distress and Safety System

GOES Geostationary Operational Environmental Satellite

GPM Global Precipitation Measurement

-HHA High Accuracy 

HD High Density 

HDOB High Density Observation 

HF High Frequency 

h hour/hours 

HLS Hurricane Local Statement

HNL Honolulu (CPHC) 

HRD Hurricane Research Division (NOAA/OAR/AOML)

HRPT High Resolution Picture Transmission 

HRV high resolution visible

-IICAO International Civil Aviation Organization 

ICMSSR Interdepartmental Committee for Meteorological Services 

and Supporting Research 

ID identification 

IFR Instrument Flight Rules 

IJPS Initial Joint Polar System

IOM International Operations Manager (FAA) 

IR Infrared 

ISRO Indian Space Research Organisation

-JJTWC Joint Typhoon Warning Center

JAXA Japan Aerospace Exploration Agency

-KKARI Korean Astronomical Research Institute

km kilometer/kilometers 

KBIX ICAO identifier for Keesler AFB, MS 

KMA Korean Meteorological Administration

KNHC ICAO identifier for the National Hurricane Center, Miami, 

FL 

kt knot/knots 

-L-
M-4

LAC Local Area Coverage 

LI Long Island 

-Mm meter/meters 

MAX maximum 

mb millibar/millibars

METEOSAT European Space Agency geostationary meteorological 

satellite 

MIA Minimum IFR Altitude 

min/MIN minute 

MiRS Microwave Integrate Retrieval System

MHS Microwave Humidity Sounder 

mph mile/miles per hour 

MSG Meteosat Second Generation

MSL Mean Sea Level

MTSAT-1R Japanese Geostationary Satellite 

MVMT movement 

-NNASA National Aeronautics and Space Administration 

NAVLANTMETOCFAC Naval Atlantic Meteorology and Oceanography Facility 

NAVMETOCCOM Naval Meteorology and Oceanography Command 

NAVOCEANO Naval Oceanographic Office 

NAVPACMETOCCEN Naval Pacific Meteorology and Oceanography Center

NAVTRAMETOCFAC Naval Training Meteorology and Oceanography Facility 

NCEP National Centers for Environmental Prediction 

(NOAA/NWS) 

NCO NCEP Central Operations 

NCWCP NOAA Center for Weather and Climate Prediction

NDBC National Data Buoy Center

NESDIS National Environmental Satellite, Data, and Information 

Service 

NHC National Hurricane Center 

NHOP National Hurricane Operations Plan 

nm nautical miles 

NOAA National Oceanic and Atmospheric Administration 

NOM National Operations Manager (FAA) 

NOTAM Notice to Airmen 

NRL Naval Research Laboratory 

NSC NOAA Science Center 

NWS National Weather Service 

NWSOP National Winter Storms Operations Plan

NWSTG National Weather Service Telecommunications Gateway
M-5

-OOAC Oceanic Aircraft Coordinator (USN) 

OB observation

OCM Ocean Colour Monitor

OFCM Office of the Federal Coordinator for Meteorological 

Services and Supporting Research 

OM Operations Manager (FAA)

OMIC Operations Manager In Charge (FAA)

OPC Ocean Prediction Center (NCEP) 

OSS Operations Support Squadron (USAF) 

-PPA Public Affairs 

PHFO ICAO identifier for Honolulu, HI 

POD Plan of the Day 

POES Polar-Orbiting Environmental Satellite 

-RRAPCON Radar Approach Control

RECCO Reconnaissance Code 

RECON reconnaissance 

ROC Radar Operations Center 

RSMC Regional/Specialized Meteorological Center (WMO)

RSO GOES Rapid Scan Operations

-SSAA Special Activity Airspace

SAB Satellite Analysis Branch 

SATCOM Satellite Communications

SATOPS 17th OWS Meteorological Satellite Operations

SCAT Scatterometer

SFC surface 

SIM Satellite Interpretation Message

SLP Sea Level Pressure 

SPC Storm Prediction Center (NCEP) 

SSM/I Special Sensor Microwave Imager (DMSP) 

SSM/IS Special Sensor Microwave Imager Sounder 

SSM/T Special Sensor Microwave Temperature Sounder 

STMC Supervisory Traffic Management Coordinator (FAA) 

SUA Special Use Airspace

-TTAFB Tropical Analysis Forecast Branch (NHC) 
M-6

TCA Aviation Tropical Cyclone Advisory 

TCD Tropical Cyclone Discussion 

TCM Tropical Cyclone Forecast/Advisories

TCP Tropical Cyclone Public Advisory 

TCPOD Tropical Cyclone Plan of the Day 

TCR Tropical Cyclone Reports

TCS Tropical Cyclone Summary

TCU Tropical Cyclone Update

TCV Tropical Cyclone Watch Warning Product

TD Tropical Depression 

TEMP temperature 

TEMP temporary 

TEMP DROP Dropwindsonde Code 

TF Thermal Fine 

TKO takeoff 

TMC Traffic Management Coordinator (FAA)

T- Dvorak number Tropical classification number 

TRMM Tropical Rainfall Measurement Mission 

TWD Tropical Weather Discussion

TWO Tropical Weather Outlook 

TWS Tropical Weather Summary

-UUAS Unmanned Aerial Systems 

UAV Unmanned Aerial Vehicle 

UCP unit control position (WSR-88D) 

UHF Ultra High Frequency 

US/U.S. United States 

USAF United States Air Force 

USCG United States Coast Guard 

USN United States Navy 

UTC Universal Coordinated Time 

-VVAS VISSR Atmospheric Sounder 

VCP volume coverage pattern (WSR-88D) 

VDM Vortex Data Message 

VIS Visible

VIIRS Visible Infrared Imaging Radiometer 

-WWEFAX Weather Facsimile 

WFO Weather Forecast Office 

WMO World Meteorological Organization 

WND wind 

WPC Weather Prediction Center (NCEP)
M-7

WPMDS Weather Product Management and Distribution System 

(Offutt AFB) 

WRA Weather Reconnaissance Area

WRS Weather Reconnaissance Squadron 

WS Weather Squadron 

WSR-88D Weather Surveillance Radar-1988 Doppler 

WT Data type header for hurricane bulletins 

WW Weather Wing

WX Weather

-ZZ Zulu (UTC)
N-1

APPENDIX N: GLOSSARY

-AAgency. Any Federal agency or organization participating in the tropical cyclone forecasting and 

warning service.

Airport Radar Service Area (ARSA). Regulatory airspace surrounding designated airports 

wherein ATC provides radar vectoring and sequencing on a full-time basis for all IFR and VFR 

aircraft. The service provided in an ARSA is called ARSA Service which includes: IFR/IFRstandard IFR separation; IFR/VFR-traffic advisories and conflict resolution; and VFR/VFRtraffic advisories and, as appropriate, safety alert. The Airman's Information Manual (AIM) 

contains an explanation of ARSA. The ARSA's are depicted on VFR aeronautical charts. 

Air Traffic Control System Command Center (ATCSCC). The FAA facility that monitors and 

manages the flow of air traffic throughout the National Airspace System (NAS), producing a 

safe, orderly, and expeditious flow of traffic while minimizing delays. The ATCSCC is a 24 hour 

a day, 7 day a week operation. 

Air Traffic Services Cell (ATSC). The Air Traffic Services Cell (DoD ATSC/ HAF/A3OP) is a 

Joint Military and Civil organization which provides liaison, facilitation, and coordination 

between emergency preparedness and operations organizations as the DoD representative.

Additionally the ATSC ensures efficient flow of DoD aircraft in response to wartime 

mobilization, contingencies, and natural disasters throughout the National Airspace System 

(NAS). The ATSC is physically located at the FAA ATC Systems Command Center, Warrenton, 

VA.

-CCenter Fix. The location of the center of a tropical or subtropical cyclone obtained by means 

other than reconnaissance aircraft penetration. See also Vortex Fix. 

Controlled Airspace. An airspace of defined dimensions within which air traffic control service 

is provided to IFR flights and to VFR flights in accordance with the airspace classification. 

• Controlled airspace is a generic term that covers Class A, Class B, Class C, Class D, and 

Class E airspace. 

• Controlled airspace is also that airspace within which all aircraft operators are subject to 

certain pilot qualifications, operating rules, and equipment requirements in 14 CFR Part 91 

(for specific operating requirements, please refer to 14 CFR Part 91). For IFR operations in 

any class of controlled airspace, a pilot must file an IFR flight plan and receive an 

appropriate ATC clearance. Each Class B, Class C, and Class D airspace area designated for 

an airport contains at least one primary airport around which the airspace is designated (for 

specific designations and descriptions of the airspace classes, please refer to 14 CFR Part 71).

• Controlled airspace in the United States is designated as follows: 
N-2

CLASS A: Generally, that airspace from 18,000 feet MSL up to and including FL 600, 

including the airspace overlying the waters within 12 nautical miles of the coast of the 48 

contiguous States and Alaska. Unless otherwise authorized, all persons must operate their 

aircraft under IFR. 

CLASS B: Generally, that airspace from the surface to 10,000 feet MSL surrounding the 

Nations's busiest airports in terms of airport operations or passenger enplanements. The 

configuration of each Class B airspace area is individually tailored and consists of a 

surface area and two or more layers (some Class B airspaces areas resemble upside-down 

wedding cakes), and is designed to contain all published instrument procedures once an 

aircraft enters the airspace. An ATC clearance is required for all aircraft to operate in the 

area, and all aircraft that are so cleared receive separation services within the airspace. 

The cloud clearance requirement for VFR operations is "clear of clouds." 

CLASS C: Generally, that airspace from the surface to 4,000 feet above the airport elevation 

(charted in MSL) surrounding those airports that have an operational control tower, are 

serviced by a radar approach control, and that have a certain number of IFR operations or 

passenger enplanements. Although the configuration of each Class C area is individually 

tailored, the airspace usually consists of a surface area with a 5 nautical mile (NM) 

radius, a circle with a 10 NM radius that extends no lower than 1,200 feet up to 4,000 feet 

above the airport elevation and an outer area. Each person must establish two-way radio 

communications with the ATC facility providing air traffic services prior to entering the 

airspace and thereafter maintain those communications while within the airspace. VFR 

aircraft are only separated from IFR aircraft within the airspace.

CLASS D: Generally, that airspace from the surface to 2,500 feet above the airport elevation 

(charted in MSL) surrounding those airports that have an operational control tower. The 

configuration of each Class D airspace area is individually tailored and when instrument 

procedures are published, the airspace will normally be designed to contain the 

procedures. Arrival extensions for instrument approach procedures may be Class D or 

Class E airspace. Unless otherwise authorized, each person must establish two-way radio 

communications with the ATC facility providing air traffic services prior to entering the 

airspace and thereafter maintain those communications while in the airspace. No 

separation services are provided to VFR aircraft. 

CLASS E: Generally, if the airspace is not Class A, Class B, Class C, or Class D, and it is 

controlled airspace, it is Class E airspace. Class E airspace extends upward from either 

the surface or a designated altitude to the overlying or adjacent controlled airspace. When 

designated as a surface area, the airspace will be configured to contain all instrument 

procedures. Also in this class are Federal airways, airspace beginning at either 700 or 

1,200 AGL used to transition to/from the terminal or en route environment, en route 

domestic, and offshore airspace areas designated below 18,000 feet MSL. Unless 

designated at a lower altitude, Class E airspace begins at 14,500 MSL over the United 

States, including that airspace overlying the waters within 12 nautical miles of the 48 

contiguous States and Alaska, up to, but not including 18,000 MSL, and the airspace 

above FL 600.

Cyclone. An atmospheric closed circulation rotating counter-clockwise in the Northern 

Hemisphere.
N-3

-EExtratropical cyclone. A cyclone (of any intensity) for which the primary energy source is 

baroclinic (i.e., results from the temperature contrast between warm and cold air masses). 

Eye. The relatively calm center of the tropical cyclone that is more than one half surrounded by 

wall cloud.

Eye Wall. An organized band of cumuliform clouds immediately surrounding the center of a 

tropical cyclone. Eye wall and wall cloud are used synonymously. 

-HHigh-Density/High-Accuracy (HD/HA) Data. Those data provided by automated airborne 

systems--WP-3s or WC-130s equipped with the Improved Weather Reconnaissance System. 

Hurricane/Typhoon. A warm-core tropical cyclone in which the maximum sustained surface 

wind speed (l-min mean) is 64 kt (74 mph) or more.

Hurricane/Typhoon/Tropical Cyclone Season. The portion of the year having a relatively high 

incidence of hurricanes/typhoons/tropical cyclones. The seasons for the specific areas are as 

follows (Note: tropical cyclones can occur during any month of the year in the Western Pacific.): 

• Atlantic, Caribbean, and the Gulf of Mexico June 1 to November 30 

• Eastern Pacific May 15 to November 30 

• Central Pacific June 1 to November 30 

• Western Pacific July 1 to December 31 

Hurricane Warning Offices. The designated hurricane warning offices follow:

• National Hurricane Center, Miami, Florida 

• Central Pacific Hurricane Center, Honolulu, Hawaii 

Hurricane/Typhoon Warning. An announcement that sustained winds of 64 knots (74 mph or 

119 km/hr) or higher are expected somewhere within the specified area in association with a 

tropical, subtropical, or post-tropical cyclone. Because hurricane preparedness activities become 

difficult once winds reach tropical storm force, the warning is issued 36 hours in advance of the 

anticipated onset of tropical-storm-force winds (24 hours for the Western North Pacific). The 

warning can remain in effect when dangerously high water or a combination of dangerously high 

water and waves continue, even though winds may be less than hurricane force.

Hurricane/Typhoon Watch. An announcement that sustained winds of 64 knots (74 mph or 119 

km/hr) or higher are possible within the specified area in association with a tropical, subtropical, 

or post-tropical cyclone. Because hurricane preparedness activities become difficult once winds 

reach tropical storm force, the hurricane watch is issued 48 hours in advance of the anticipated 

onset of tropical storm force winds.
N-4

-IICAO-Controlled Airspace. An airspace of defined dimensions within which air traffic control 

service is provided to IFR flights and to VFR flights in accordance with the airspace 

classification. (Note: Controlled airspace is a generic term which covers Air Traffic Service 

airspace Classes A, B, C, D, and E).

-MMajor Hurricane. A "major" hurricane is one that is classified as a Category 3 or higher. 

Maximum 1-Min Sustained Surface Wind. When applied to a particular weather system, refers 

to the highest 1-minute average wind (at an elevation on 10 meters with an unobstructed 

exposure) associated with that weather system at a particular point in time. 

Micronesia. An area defined by the Commonwealth of the Northern Marianas Islands, the 

Republic of Palau, the Federated States of Micronesia, and the Republic of the Marshall Islands.

Miles. The term "miles" used in this plan refers to nautical miles (nm) unless otherwise 

indicated. 

Mission Identifier. The nomenclature assigned to tropical and subtropical cyclone aircraft 

reconnaissance missions for weather data identification. It's an agency-aircraft indicator followed 

by a Chief, Aerial Reconnaissance Coordination, All Hurricanes (CARCAH) assigned missionsystem indicator. 

-NNational Operations Manager. Supervisor in charge of operations of the Air Traffic Control 

System Command Center.

National Traffic Management Specialist. ATCSCC personnel responsible for the active 

management of traffic throughout the NAS.

-OOperations Manager. Supervisor in charge of operations of an FAA Terminal Radar Approach 

Control (TRACON).

Operations Manager in Charge. Supervisor in charge of operations of an FAA Air Route 

Traffic Control Center (ARTCC).

-PPost-Tropical Cyclone. A former tropical cyclone. This generic term describes a cyclone that no 

longer possesses sufficient tropical characteristics to be considered a tropical cyclone. Posttropical cyclones can continue carrying heavy rains and high winds. Note that former tropical 
N-5

cyclones that have become fully extratropical, as well as remnant lows, are two specific classes 

of post-tropical cyclones. 

Present Movement. The best estimate of the movement of the center of a tropical cyclone at a 

given time and at a given position. This estimate does not reflect the short-period, small-scale 

oscillations of the cyclone center. 

-RReconnaissance Aircraft Sortie. A flight that meets the requirements of the tropical cyclone 

plan of the day.

Relocated. A term used in an advisory to indicate that a vector drawn from the preceding 

advisory position to the latest known position is not necessarily a reasonable representation of 

the cyclone's movement. 

Remnant Low. A post-tropical cyclone that no longer possesses the convective organization 

required of a tropical cyclone and has maximum sustained winds of less than 34 kt. The term is 

most commonly applied to the nearly deep-convection-free swirls of stratocumulus in the eastern 

North Pacific. 

-SSpecial Activity Airspace. Any airspace with defined dimensions within the National Airspace 

System wherein limitations may be imposed upon aircraft operations. This airspace may be 

restricted areas, prohibited areas, military operations areas, air ATC assigned airspace, and any 

other designated airspace areas. The dimensions of this airspace are programmed into URET and 

can be designated as either active or inactive by screen entry. Aircraft trajectories are constantly 

tested against the applicable sectors when violations are predicted. 

Special Use Airspace. Airspace of defined dimensions identified by an area on the surface of the 

earth wherein activities must be confined because of their nature and/or wherein limitations may 

be imposed upon aircraft operations that are not a part of those activities. Types of special use 

airspace are: 

a. Alert Area- Airspace which may contain a high volume of pilot training activities or an 

unusual type of aerial activity, neither of which is hazardous to aircraft. Alert Areas are 

depicted on aeronautical charts for the information of nonparticipating pilots. All activities 

within an Alert Area are conducted in accordance with Federal Aviation Regulations, and 

pilots of participating aircraft as well as pilots transiting the area are equally responsible for 

collision avoidance. 

b. Controlled Firing Area- Airspace wherein activities are conducted under conditions so 

controlled as to eliminate hazards to nonparticipating aircraft and to ensure the safety of 

persons and property on the ground. 

c. Military Operations Area (MOA)- A MOA is airspace established outside of Class A 

airspace area to separate or segregate certain nonhazardous military activities from IFR 

traffic and to identify for VFR traffic where these activities are conducted. 

d. (Refer to AIM.)
N-6

e. Prohibited Area- Airspace designated under 14 CFR Part 73 within which no person may 

operate an aircraft without the permission of the using agency.

(Refer to AIM.)

(Refer to En Route Charts.)

f. Restricted Area- Airspace designated under 14 CFR Part 73, within which the flight of 

aircraft, while not wholly prohibited, is subject to restriction. Most restricted areas are 

designated joint use and IFR/VFR operations in the area may be authorized by the controlling 

ATC facility when it is not being utilized by the using agency. Restricted areas are depicted 

on en route charts. Where joint use is authorized, the name of the ATC controlling facility is 

also shown. 

(Refer to 14 CFR Part 73.) 

(Refer to AIM.)

g. Warning Area- A warning area is airspace of defined dimensions extending from 3 nautical 

miles outward from the coast of the United States, that contains activity that may be 

hazardous to nonparticipating aircraft. The purpose of such warning area is to warn 

nonparticipating pilots of the potential danger. A warning area may be located over domestic 

or international waters or both.

Storm Surge. An abnormal rise in sea level accompanying a hurricane or other intense storm, 

and whose height is the difference between the observed level of the sea surface and the level 

that would have occurred in the absence of the cyclone. Storm surge is usually estimated by 

subtracting the normal or astronomic tide from the observed storm tide.

Storm Tide. The actual level of sea water resulting from the astronomic tide combined with the 

storm surge. 

Subtropical Cyclone. A non-frontal low-pressure system that has characteristics of both tropical 

and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones 

that originate over tropical or subtropical waters, and have a closed surface wind circulation 

about a well-defined center. In addition, they have organized moderate to deep convection, but 

lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant 

proportion of their energy from baroclinic sources, and are generally cold-core in the upper 

troposphere, often being associated with an upper-level low or trough. In comparison to tropical 

cyclones, these systems generally have a radius of maximum winds occurring relatively far from 

the center (usually greater than 60 nm), and generally have a less symmetric wind field and 

distribution of convection.

Subtropical Depression. A subtropical cyclone in which the maximum sustained surface wind 

speed (l-min mean) is 33 knots (38 mph) or less. 

Subtropical Storm. A subtropical cyclone in which the maximum sustained surface wind speed 

(1-min mean) is 34 knots (39 mph) or higher. 

Super Typhoon. A "super" typhoon is one that is classified as having winds of 130 knots (150 

mph) or greater. 
N-7

Sustained Surface Wind. The 1-minute averaged wind at the 10-meter elevation with an 

unobstructed exposure. 

Synoptic Surveillance (formerly Synoptic Track).Weather reconnaissance mission flown to 

provide vital meteorological information in data sparse ocean areas as a supplement to existing 

surface, radar, and satellite data. Synoptic flights better define the upper atmosphere and aid in 

the prediction of tropical cyclone motion and intensity. 

-TTropical Cyclone. A warm-core, non-frontal synoptic-scale cyclone, originating over tropical or 

subtropical waters, with organized deep convection and a closed surface wind circulation about a 

well-defined center.

Tropical Cyclone Plan of the Day. A coordinated mission plan that tasks operational weather 

reconnaissance requirements during the next 1100 to 1100Z UTC day or as required, describes 

reconnaissance flights committed to satisfy both operational and research requirements, and 

identifies possible reconnaissance requirements for the succeeding 24-hour period. 

Tropical Depression. A tropical cyclone in which the maximum sustained surface wind speed 

(l-min mean) is 33 kt (38 mph) or less. 

Tropical Disturbance. A discrete tropical weather system of apparently organized convection--

generally 100 to 300 mi in diameter--originating in the tropics or subtropics, having a nonfrontal 

migratory character, and maintaining its identity for 24 hours or more. It may or may not be 

associated with a detectable perturbation of the wind field. 

Tropical Storm. A tropical cyclone in which the maximum sustained surface wind speed (l-min 

mean) ranges from 34 kt (39 mph) to 63 kt (73 mph).

Tropical Storm Warning. An announcement that sustained winds of 34 to 63 knots (39 to73 

mph or 63 to 118 km/hr) are expected within 36 hours within the specified coastal area in 

association with a tropical, subtropical or post-tropical cyclone. NHC, CPHC, and WFO Guam 

issue warnings when conditions are expected within 36 hours. 

Tropical Storm Watch. An announcement that sustained winds of 34 to 63 knots (39 to 73 mph 

or 63 to 118 km/hr) are possible somewhere in the specified area within 48 hours in association 

with a tropical, subtropical or post-tropical cyclone. NHC, CPHC, and WFO Guam issue 

watches when conditions are possible within 48 hours. 

Tropical Wave. A trough or cyclonic curvature maximum in the trade-wind easterlies. The wave 

may reach maximum amplitude in the lower middle troposphere or may be the reflection of an 

upper tropospheric cold low or equatorial extension of a middle latitude trough. 

Tropical Weather System. A designation for one of a series of tropical weather anomalies. As 

such, it is the basic generic designation, which in successive stages of intensification, may be 

classified as a tropical disturbance, wave, depression, storm, or hurricane. 

Typhoon/Hurricane. A warm-core tropical cyclone in which the maximum sustained surface 

wind speed (l-min mean) is 64 kt (74 mph) or more.
N-8

-UUncontrolled Airspace (Class G Airspace).That portion of the airspace that has not been 

designated as Class A, Class B, Class C, Class D, or Class E and within which Air Traffic 

Control has neither the authority nor the responsibility for exercising control over air traffic.

-VVortex Fix. The location of the surface and/or flight level center of a tropical or subtropical 

cyclone obtained by reconnaissance aircraft penetration. See Center Fix, also. 

-WWall Cloud. An organized band of cumuliform clouds immediately surrounding the center of a 

tropical cyclone. Wall cloud and eye wall are used synonymously.