3.3

 

Providing a tactical thunderstorm product 

to FAA air traffic managers 

Dennis M. Rodgers1, Young Chun2, James Frimel2, Lisa Gifford2, Greg Pratt 

NOAA Research – Forecast Systems Laboratory 

Boulder, Colorado 

 

Thomas Amis 

National Weather Service, Center Weather Service Unit 

Fort Worth, Texas 

 

1 Corresponding author address: Dennis M. Rodgers, NOAA/OAR/FSL FS5, 325 Broadway, Boulder, CO 

80305-3328; email: dennis.m.rodgers@noaa.gov 

2 In collaboration with the Cooperative Institute for Research in the Atmosphere (CIRA), Colorado State 

University, Fort Collins, Colorado

1. INTRODUCTION 

Responding to FAA requirements, NOAA Forecast 

Systems Laboratory (FSL), in conjunction with the 

NWS Prototype Aviation Collaborative Effort 

(PACE), is developing a graphic display of tactical 

thunderstorm information. This tactical convective 

hazard product (TCHP) depicts current hazardous 

thunderstorms and 2-h forecast of hazardous 

thunderstorm positions. This automated product, 

generated every five minutes, is intended to support 

tactical air traffic decision-making. The TCHP is 

designed to capitalize on development of advanced 

products from the FAA Aviation Weather Research 

Program (AWRP: AUA-430) and to optimize the use 

of conventional advisories. Our goal in creating the 

TCHP is to consolidate all NWS thunderstorm 

products relevant to tactical decision making into a 

single (or layered) graphical product. 

The TCHP was evaluated at the Fort Worth Air 

Route Traffic Control Center (ARTCC – 

operationally designated ZFW) during a portion of 

the 2003 warm season. The version of the TCHP 

evaluated consisted of detection and forecast 

information contained in the National Convective 

Weather Forecast (NCWF) and Convective 

SIGMETs. FAA AWRP developed the NCWF, and 

NWS/Aviation Weather Center forecasters produce 

Convective SIGMETs. 

 

User feedback from the TCHP evaluation resulted 

in requirements for a graphical tactical 

thunderstorm product for use by air traffic 

managers. Recommendations for the content and 

presentation of a TCHP are refined and its utility to 

operations is affirmed through the process of 

familiarizing the users with the characteristics of the 

product, demonstrating the product in an 

operational setting, and evaluating the product 

through feedback from the ZFW Traffic 

Management Unit (TMU) participants. 

The sponsors of this project are: 

• FAA Air Traffic System Requirements 

(ARS-100) 

• FAA Aviation Weather Research Program 

(AUA-430) 

• FAA Southwest Region Headquarters 

• National Weather Service Southern Region 

Headquarters 

Participants in this evaluation represent a multiagency collaboration. The NWS Southern Region 

Headquarters PACE project provided computer 

hardware and a high-speed (DSL) Internet 

connection; FSL provided software development 

and meteorological support; ZFW management 

hosted the evaluation and endorsed the 

participation of TMU traffic managers and 

supervisors; and the ZFW Center Weather Service 

Unit (CWSU) provided an area for PACE activities. 

The common goals of PACE and of the FAA TMU 

Weather Needs Project allowed beneficial 

leveraging of resources. FSL Aviation Division’s 
participation is in response to requirements and 

funding by the FAA Aviation Weather Research 

Program (AUA-430). 

2. BACKGROUND 

2.1 Reference Documents 

Two documents have guided this work. FAA 1999 

documents the results of an in-depth user needs 

analysis of weather information used in tactical air 

traffic decision-making. FAA 2002 sets forth 

requirements (master, supporting, and interim) for 

tactical convective forecasts for FAA traffic 

managers. TCHP is an initial step toward 

addressing unmet or newly identified weather 

information requirements of the Traffic Management 

Unit. 

2.2 Initial Requirements 

A TMU Weather Needs Core Working Group was 

formed to address the above documented weather 

information requirements, beginning with 

convection products. At a meeting at ZFW in 

October 2002, the Core Working Group determined 

that initial requirements for a TCHP shall include 5-

min updated graphical depictions of: 

• NCWF Detection 

• NCWF 1-h forecast 

• NCWF Tops and Movement 

• C-SIGMET Nowcast 

• C-SIGMET 1-h forecast 

• C-SIGMET text 

Another NWS product, which was considered for 

inclusion in TCHP, is the Center Weather Advisory 

(CWA). The CWA, issued by CWSUs, is a weather 

warning for conditions meeting or approaching 

AIRMET, SIGMET, or Convective SIGMET criteria. 

CWAs may be issued for a number of adverse 

weather conditions, including thunderstorms, and 

contain free-form text. Therefore decoding is 

necessary to discriminate thunderstorm CWAs from 

the rest. The decision was made to postpone 

inclusion of the CWA until it can be produced in a 

standardized machine-readable format. 

2.3 Development Environment 

Development of the TCHP was preceded by 

establishing the PACE Facility within the ZFW 

CWSU. In order to perform exploratory 

development in a rapid prototyping environment, a 

meteorological workstation isolated from ZFW 

operational systems was necessary. The FSL 

visualization platform called FX-Collaborate (FXC) 

was installed at the CWSU with a high-speed 

Internet connection to servers at FSL. Descriptions 

of FXC and PACE can be found in FSL 2004 and 

Rodgers and Amis 2002, respectively. NWS 2002 

describes the concept of operations of PACE at 

ZFW. 

The first software engineering requirement involved 

decoding and creating AWIPS graphics for the 

TCHP components. Next, those products were 

integrated into the FXC menus and data stream, 

and FXC was enhanced with aviation map 

selections and tailored for use in ZFW airspace. 

Pace’s FXC display system could then be used to 

test and validate early versions of the product. 

The PACE exploratory development facility proved 

to be an effective test bed for the TCHP 

development. Before the product was made 

available to TMU traffic managers, the PACE Chief 

and CWSU forecasters were able to examine TCHP 

components in their preliminary state on FXC. 

Based on their initial feedback, and comments 

solicited from TMU supervisors, new requirements 

were defined to change the background and map 

overlay colors to be consistent with the Integrated 

Terminal Weather System (ITWS) display. A 

second requirement was to provide animation. 

These modifications were implemented before the 

beginning of the evaluation. By incorporating the 

initial feedback from PACE, we were able to 

increase the likelihood that the product would be 

acceptable to the TMU users. 

This iterative development/feedback process 

represents rapid prototyping in a spiral software 

development model. In the spiral development 

model, an initial build is presented, feedback is 

gathered, requirements are added or modified, and 

improvements are incorporated at phased intervals. 

The TCHP is an evolutionary prototype in this 

development model. An evolutionary prototype, by 

definition, is built in a quality manner, experienced 

by the users, and evolved to better meet needs. 

The process is repeated as needed. This type of 

prototyping is flexible in that modified or added 

requirements and technological improvements may 

be incorporated quickly and efficiently. 

The PACE FXC system provided powerful 

capabilities to the evaluation. For the first time 

anywhere on any display system, we had the ability 

to view all of the TCHP components together with 
animating NEXRAD mosaic images as well as

observations and analyses from the NWS AWIPS 

data stream. This allowed the CWSU/PACE 

meteorologists to examine TCHP performance, and 

to verify comments made by the TMU users 

regarding movement and forecast information from 

the NCWF. These unique animated displays also 

revealed skill in the C-SIGMET 1-h forecast when 

subjectively compared to the observations from the 

NEXRAD mosaic and NCWF detection field 

animations. 

3. TCHP DESCRIPTION 

3.1 TCHP Web-based Viewer

We made the TCHP available for viewing on a 

password-protected web site accessible via the 

Internet. This approach is cost effective and poses 

no impact to ZFW operational systems. Links are 

available on the home page to documentation, 

publications, and a project contact list. In the center

of the home page, a link invokes the Tactical 

Convective Hazards Product Viewer. The TCHP 

Viewer initializes with a default display on the 

ARTCC scale, including State, ARTCC, and 

Dallas/Fort Worth (DFW) and Houston (IAH) 

Terminal Approach Control (TRACON) boundaries, 

aviation location identifiers, and sets of selectors for 

CONUS, Houston Center, or TRACON displays, as 

well as a selection of data and map overlays, and a 

selector for an animated view. 

3.2 TCHP Graphical Content 

The evaluated version of the TCHP graphical 

display contains the following components: 

• NCWF Detection Field 

• NCWF 1-h forecast 

• Hazard Tops and Movement 

• C-SIGMET Nowcast 

• C-SIGMET 1-h forecast

• C-SIGMET Text 

• Impacted Jet Route Display 

Components of the TCHP may be displayed in any 

combination. The default display includes Hazard 

Detection, Tops & Movement, and NCWF 1-hr

forecast (Fig. 1). The three selectable C-SIGMET 

overlays on the TCHP selector menu are graphics 

derived from the conventional text Convective 

SIGMET. The C-SIGMET Nowcast graphic is the 

area polygon, line, or point as issued in the 

operational text Convective SIGMET. The CSIGMET 1-h forecast, unique to this project, is a 

graphic produced on the NCWF 5-min cycle, 

depicting the extrapolated position of the CSIGMET polygon 1 h from the current clock time, 

time-matched to the current NCWF 1-h forecast. In 

other words, the C-SIGMET 1-h forecast positions

are valid at 1 h after issue time and updated every 5 

min to be valid up to 1 h, 55 min after issue time. 

The latest C-SIGMET 1-h Fcst is valid at the same 

time as the latest NCWF 1-h forecast. The 

extrapolated position of the C-SIGMET 1-h forecast 

is based on the thunderstorm area movement given 

in the operational Convective SIGMET text. 

Figure 1. TCHP default display. 

The Impacted Jet Route tactical decision aid (TDA; 

Fig. 2) is a proof-of-concept exercise involving a 

modest investment of developer time to produce a 

simple, "quick-look" graphic indicating

thunderstorm-impacted air space. In this simplified 

presentation of the TCHP information, current and 

forecasted impact to specific jet routes can be 

determined at a glance. A subset of high-use jet 

routes are depicted in one of three colors: Green jet 

route segments indicate no direct impact from 

NCWF detected or forecast thunderstorms; Red jet 

route segments indicate impact from NCWF 

Detection level 3 or greater touching the jet route 

segment; Yellow jet route segments indicate a 

NCWF forecast polygon touching the jet route. This 

display concept offers a "red light/green light" 

simplified graphic display of weather impacted 

airspace, and could be easily extended to highlight 

sectors, approach/departure corridors and gates, 

etc. in addition to jet routes. Other automated, 
gridded hazardous weather diagnostic and forecast 

information (for example, icing and turbulence) 

could also be integrated into this type of display. 

This experimental TDA was included with the TCHP 

for traffic manager comments. 

3.3 Display Interface 

The left side of the TCHP Viewer contains controls

for user-selectable data and map overlays, and five 

“radio buttons” for the five geographic areas; 

CONUS, ZFW ARTCC, ZHU ARTCC, DFW 

TRACON, IAH TRACON. Above the scale selector

buttons, two sets of check boxes allow the user to 

select/deselect data and map overlays. 

A link below the scale selector buttons initializes an 

animation of the TCHP. The animation 

automatically loads and refreshes 6 detection 

images at 15-min intervals, providing 90 min of 

history. The seventh frame shows the most recent

Detection with the most recent NCWF 1-h forecast 

and Tops & Movement overlays. 

The web-based TCHP viewer enabled TMU staff to 

experience the TCHP concept and content, but was 

not intended to be a comprehensive display system 

including all necessary operational functionality, 

such as extensive map overlay selections and 

aircraft situation information. The TMU participants 

frequently called those capabilities requirements. 

Nevertheless, the web display was an adequate 

cost-effective way to gather necessary feedback on 

the thunderstorm information content and 

presentation of the TCHP.

Fig. 2. Impacted Jet Route Product. 

4. EVALUATION DESCRIPTION 

4.1 Training

Nearly all traffic managers, traffic management 

coordinators and the CWSU meteorologists have 

completed training to become familiar with the use 

and interpretation of the thunderstorm products 

included in the TCHP. Additionally, participants 

were briefed on the evaluation plan and trained in 

the use of the project’s TMU web site to view the 

TCHP and associated displays. Once they became 

familiar with the components of the TCHP, TMU 

and CWSU participants were asked to provide 

feedback on the utility of the TCHP and suggestions 

for improvements. 

Training of TMU traffic managers began on 04 June 

and was completed on 27 June, with a total of 23 

participants attending a PowerPoint presentation 

individually or in pairs. The training sessions 

averaged 45 min in duration. The CWSU MIC 

completed some initial training in February and 

March 2003 but that training was limited to two 

TMU supervisors to facilitate early feedback 

gathering. Further training at that point had limited 

success due to changes in the TMU staff, changes 

in the TCHP web design, and the routine demands 

of MIC management duties. 

4.2 Schedules and Location 

The TCHP evaluation is located at the Fort Worth, 

TX ARTCC (ZFW). This site was selected due to 

the high volume of air traffic, technological 

advances, thunderstorm climatology, and location

with respect to NWS/FAA regional headquarters. 

The CWSU is located within the Display System 

Replacement (DSR) Control Room next to the 

Operations Manager and TMU. This design 

facilitates a rapid flow of air traffic and weather data 

for use in tactical and strategic planning. The 

ARTCC operations floor is divided into two main 

areas: the DSR control room containing radar and 

monitor positions for controllers; and the traffic 

management area, in which TMU controllers, 

supervisors, and operations managers oversee all 

facets of air traffic through ZFW's airspace. The 

CWSU operates as part of the traffic management 

team. 

4.3 TCHP displays in an Operational Setting 

In general, the TCHP was displayed in the TMU 

alongside the Convective Collaborative Forecast 

Product (CCFP) during Strategic Planning 
telephone conference calls in which strategic and 

tactical planning of aircraft movement through the 

National Airspace System (NAS) is conducted. 

TMU supervisors and coordinators viewed TCHP at 

the TMU supervisory position, which is the hub of 

information flow within the TMU. This is where 

coordination of all traffic flow from the en-route 

airspace into the Dallas/Fort Worth (DFW) 

TRACON and terminal airspace occurs. 

In the CWSU, TCHP was displayed at the PACE 

operations computer and desktop computers with 

Internet connectivity. Occasionally, TCHP was 

displayed via a large screen plasma monitor to the 

traffic management and control room supervisory 

staff during daily operational briefings. 

4.4 Data Collection and Analysis Method 

The following information was obtained through 

one-on-one interviews with TMU traffic managers 

and supervisors, and through comments and 

discussions that occurred during training. Each 

individual respondent was trained and had ample 

opportunity to view the TCHP in real time during 

several active thunderstorm periods in June. 

Fourteen TMU traffic managers or supervisors (out 

of the 23 trained) provided feedback used in this 

report, representing 60% of the ZFW TMU staff. 

The CWSU MIC recorded their responses on a 

web-based TCHP evaluation form. Responses 

recorded on the evaluation web site were compiled 

and tallied, and combined with user comments to 

support this report. 

5. FINDINGS AND RECOMMENDATIONS 

5.1 Findings 

Several significant findings resulted from this 

operational assessment. 

• Traffic managers unanimously endorse the 

TCHP concept and most approved of the 

TCHP graphical display. 

• The NCWF is subject to erroneous motion 

vectors and extrapolated storm positions 

and, therefore, was considered 

insufficiently reliable to use in air traffic 

management decisions. 

• Traffic managers do not use Convective 

SIGMETs. 

• C-SIGMET 1-h extrapolated forecast 

graphic was useful when combined with 

NCWF Detection. 

• A direct benefit of conducting this 

evaluation is risk reduction in the 

operational implementation of a TCHP. A 

secondary benefit is the opportunity to “fine 

tune” the content and presentation of a 

graphic product prior to national 

implementation. 

5.2 Recommendation for a Tactical Convective 

Hazard Product 

Based on the unanimous positive response of our 

sample group of ZFW TMU traffic managers and 

supervisors, implementation of a graphical tactical 

thunderstorm product is recommended, but 

additional prototyping is recommended to ensure 

maximum utility. The findings of this assessment 

indicate that this tactical product should include the 

following characteristics or attributes: 

• 0-2 h time frame for tactical applications 

• NCWF detection field with existing intensity 

levels and colors 

• Enhanced NCWF forecast graphic (1 h 

initially; 2 h when approved by Aviation 

Weather Technology Transfer Board) 

• Tops and Movement graphic 

• Selectable NCWF Performance graphic 

• Selectable Convective SIGMET 1-h 

forecast graphic showing extrapolated 

positions time-matched to the NCWF 

production cycle. 

• Selectable CCFP 2-, 4-, and 6-h graphics 

• Selectable sector and jet route map 

backgrounds (similar to ETMS or ITWS 

capabilities) 

• Selectable aircraft locations graphic 

• Typical user interactivity, e.g., zoom, pan, 

animate 

• Graphic presentation that is visually 

consistent with ITWS displays (neutral gray 

background; consistent map overlay 

selections and colors; etc.) 

The evaluation team suggests including a 

performance graphic, showing the previous hour’s 

forecast with the current detection field, as is found 

on the ADDS (Aviation Digital Data Service: 

http://adds.aviationweather.gov/) presentation of 

NCWF. By including a performance graphic with 

the TCHP and by providing the capability to overlay 

a time-matched extrapolated C-SIGMET forecast, 

uncertainties or gaps in forecast information with 

the automated product may be “filled in” with the 
less frequent human product, or flagged by the 

performance graphic. The performance graphic 

included in the ADDS NCWF graphics package 

provides a simple, visual method for quickly 

assessing the "goodness" of the NCWF in a given 

situation. This strategy maximizes the utility of both 

the conventional human-generated advisories and 

the frequently updated automated product. 

TMU respondents to the evaluation questionnaire 

indicated that the TCHP is most useful on the 

ARTCC scale, including a 150 nautical mile buffer 

outside of the ARTCC airspace. A conterminous 

US graphic would be useful with zoom and roam 

capability, applied to transcontinental overflight 

traffic decision-making. Most felt that ITWS is a 

superior display for gate and terminal area decisionmaking. 

Since the NCWF Detection is a hybrid product 

containing derived radar information and lightning, 

and differs in appearance and information content 

from a conventional radar reflectivity display, some 

training for users is strongly indicated. 

5.3 General Recommendations 

Based on the findings of this assessment, the 

evaluation team recommends that all future 

automated forecast products include real-time 

performance information as part of the operational 

graphics package as a requirement for approval for 

use by non-meteorologist end users. A 

performance graphic, such as is found on the 

ADDS presentation of NCWF, or a similar real-time 

verification graphic, facilitates the intelligent 

application of, and confidence in, the product by 

end users. 

Based on the limited positive responses from users, 

refinement of the Impacted Jet Route TDA 

according to the feedback obtained, and further 

evaluation of its utility in tactical decision making 

are justified. 

6. NEXT VERSION OF TCHP 

Work is underway implementing many of the 

recommended changes to the TCHP. Foremost of 

these improvements is implementation of the 

NCWF-2. This formulation of NCWF provides 1-

and 2-h probability forecasts of significant 

thunderstorms, updated every five minutes. 

(Addition of the 2-h NCWF-2 to the TCHP is 

contingent upon approval by the Aviation Weather 

Technology Transfer Board.) The probabilities are 

shown as fields of lighter and darker shades, where 

lighter shades indicate higher probability areas, and 

darker shades indicate lower probability areas. 

Regions of thunderstorm growth are captured by 

use of Rapid Update Cycle (RUC) model gridded 

forecasts, along with radar echo trending and 

diurnal considerations. Dissipation is trended 

based on storm area coverage. Improvements have 

also been made to the motion vector calculations. 

NCWF-2 uses RUC steering flow winds to forecast 

motions for small storms when history is not 

available. We anticipate that these improvements 

will largely eliminate some of the primary criticisms 

of NCWF, such as lack of forecast movement on 

young and/or small storms, delay of forecast when 

storms are growing with limited storm history, and 

intermittent storm motion forecasts when storm size 

is near the minimum area threshold. 

In order to extend the forecast period of the TCHP 

to 2 h, Collaborative Convective Forecast Product 

(CCFP) graphics were added as selectable 

overlays. This is largely in response to 

requirements from the TMU users, who already 

routinely used the CCFP and wanted an integrated 

thunderstorm display including the CCFP. When 

the NCWF-2 is approved for the 2h forecast, it will 

be implemented into the TCHP. 

6.1 Tactical Decision Aid development 

The Impacted Jet Route TDA has been enhanced 

according to feedback from the 2003 evaluation, 

and development of Sector and 

Approach/Departure Corridor TDAs based on 

TCHP information is underway. Like the Impacted 

Jet Route TDA, impacted sectors and corridors will 

be color coded according to current and forecast 

significant thunderstorm impact. 

6.2 2005 Evaluation 

All enhancements will be completed during 

fall/winter, with a final quasi-operational evaluation 

planned for the 2005 convective season. Final 

recommendations for operational implementation of 

a graphical tactical convective hazard product for 

FAA traffic managers will be produced following the 

2005 evaluation. 

 

7. ACKNOWLEDGMENTS 

This work is in response to requirements and 

funding by the Federal Aviation Administration. The 
views expressed are those of the authors and do 

not necessarily represent the official policy or 

position of the FAA or NWS. 

A version of this paper was presented at the 20th

Conf. on Weather Analysis and Forecasting, 

Seattle, WA, January 2004. 

8. REFERENCES 

FAA, 1999: Decision-Based Weather Needs for the 

Air Route Traffic Control Center (ARTCC) TMU. 

Federal Aviation Administration, Air Traffic Systems 

Requirements, ARS-100, Washington, D.C. 

November 1999, 21 pp. 

FAA, 2002: Weather Forecast Requirements in 

Support of the En Route Traffic Management Unit; 

Convection Products, Version 1.0. Federal Aviation 

Administration, Air Traffic Systems Requirements, 

ARS-100, Washington, D.C., July 2002, 25 pp 

FSL, 2004: FXC Users' Guide. NOAA Research - 

Forecast Systems Laboratory, 325 Broadway, 

Boulder CO 80305. [Available online at: 

http://wwwsdd.fsl.noaa.gov/~fxa/FXC/fxcug/FXC_User_Guide.

html] 

NWS, 2002: Prototyping Aviation Collaboration 

Effort (PACE) concept of operations at the Fort 

Worth ARTCC CWSU. National Weather Service 

Southern Region Headquarters, Fort Worth, TX, 22 

pp. 

Rodgers, D.M., and T. Amis, 2002: Applying FXConnect to the Prototype Aviation Collaboration 

Effort at the Ft. Worth Air Route Traffic Control 

Center. Preprints, 10th Conf on Aviation, Range, 

and Aerospace Meteorology, Portland, OR, Amer. 

Meteor. Soc, Boston, MA, pp 277-280.