Number range CHAPTER **CHAPTER 3**

**GENERAL OPERATIONS AND PROCEDURES**

**3.1 [General.]{.underline}** Every effort has been made to standardize
terminology, adopt common definitions, and adjust criteria to a common
base; however, each agency has different operational watch and warning
criteria that must be met. Although standardization will be used
wherever possible in forecasts and warnings, each agency retains the
right to specify the forecast, watch and warning criteria needed to
carry out its mission.

**3.2** **[National Weather Service (NWS) Watch/Warning
Procedures.]{.underline}**

**3.2.1 General.** The NWS has statutory responsibility for providing a
severe local storms watch and warning service for all 50 States. This
responsibility is fulfilled by the National Centers for Environmental
Prediction (NCEP) Storm Prediction Center (SPC) and the NWS Weather
Forecast Offices (WFOs). NCEP Central Operations (NCO), as the central
data processing center for the NWS, issues prognostic charts,
discussions, and other forecast data and information, that are used by
the WFOs, SPC, and NCEP's Aviation Weather Center (AWC) in fulfilling
their severe local storm responsibilities.

**3.2.1.1** **Geographical Responsibilities.** For the conterminous
U.S., the SPC issues Severe Weather Outlooks and Watches. SPC does not
issue severe local storm watches for Alaska or Hawaii. The WFOs at
Anchorage and Honolulu have the responsibility for maintaining weather
watches and issuing warnings as needed for their respective states. Each
WFO in the 50 states and the U.S. territories, located in the NWS
Pacific and Southern Regions, issues a Thunderstorm Outlook/Hazardous
Weather Outlook for a forecast of and Warnings for imminent severe
thunderstorms and/or tornadoes.

**3.2.1.2 Watch/Warning Criteria.** Any or all of the criteria listed in
para. 2.2 Severe Local Storms, para. 2.5 Density/Risk of Severe
Thunderstorms**,** and para. 2.6 Thunderstorm Intensity
Categories/Severe Thunderstorms may be mentioned in severe weather
watches/warnings to indicate more fully that severe weather is expected.
Severe weather watches/warnings that mention tornadoes or waterspouts
imply that thunderstorm activity, usually severe, also is
expected/occurring.

**3.2.1.3 Outlooks** The SPC issues separate Convective Outlooks for
severe weather for Day One, Day Two, and Day Three. Each forecast covers
24 hours (see Figure 3-1), in both a text and graphical format. The
outlook conveys forecasts of expected severe weather coverage as defined
in Chapter 2. Additionally, the Day 1 and Day 2 Outlook cover the
general thunderstorm outlook, where greater than a 10 percent chance of
a thunderstorm is forecast. A Day 4-8 Severe Weather Outlook is also
issued to indicate areas where a severe potential exists several days in
the advance. A relatively high confidence for severe weather has to be
expected before an area is indicated, given the greater uncertainty.
Each WFO issues a Thunderstorm Outlook/Hazardous Weather Outlook to
outline the severe convective threats of the day, public watches based
on SPC watches, and public warnings for imminent severe thunderstorms
and/or tornadoes.

**3.2.1.4 Mesoscale** **Discussions** **The** SPC issues Mesoscale
Discussions (MD) to convey to CONUS WFOs, the public, media, and
emergency managers the current meteorological reasoning for short-term
hazardous weather concerns. MCDs are non-scheduled, event-driven
products. SPC uses the Mesoscale Discussion (MD) to alert WFOs and
various customers to different types of short-term weather hazards. For
severe potential and convective trends SPC will issue a MD 1 to 2 hours
prior to a watch issuance. SPC will also issue a MD for severe weather
potential when an area is being monitored for a potential convective
watch, or when thunderstorm development is potentially severe, but will
not have enough areal coverage or duration to need a convective watch
issuance. MDs are normally issued at least every 2 to 3 hours for each
convective watch that is in effect and focus on mesoscale and storm
scale features within the watch area. For an example of a MD see
Appendix A.

The following descriptions are used in the MD "CONCERNING..." line to
better identify the reasoning behind the particular SPC discussion:

Severe Potential

Watch Unlikely

Watch Possible

Watch Likely

Tornado Watch Likely

Severe Thunderstorm Watch Likely

Watch Needed Soon

**3.2.1.4** **Public Watches.**

**3.2.1.4.1 SPC.** The SPC collaborates on watch issuances with the
local Weather Forecast Offices and issues watches where severe
thunderstorms and/or tornadoes are expected (see Appendix A for an
example of a Severe Weather Watch). A Watch Outline Update (WOU) is also
issued that lists all of the counties, and if applicable, coastal zones
that are in the watch issuance. (see Appendix A for an example of a WOU)
The watch type reflects the anticipated predominant threat. A tornado
watch is issued where multiple weak tornadoes or at least one strong
tornado is anticipated. A severe thunderstorm watch is issued when hail
and/or thunderstorms producing damaging winds or large hail are expected
to be the primary threat.

**3.2.1.4.1.1 Watch Status Message.** Following the issuance of a severe
thunderstorm or tornado watch, the Storm Prediction Center issues hourly
watch status messages indicating which areas remain under the threat of
severe weather (see Appendix A for an example of a Watch Status
message).

**3.2.1.4.1.2 Aviation Watch.** Accompanying the Public severe
thunderstorm or tornado watch is the Aviation version of the same watch,
which outlines the watch area for plotting purposes (see Appendix A for
an example of an Aviation Watch). This watch also includes the expected
maximum hail size, strongest thunderstorm wind gusts and storm motion
vector of severe thunderstorms in the watch area.

**3.2.1.4.2 WFO.** Once a watch is issued by SPC, the WFO issues a Watch

County Notification (WCN) listing of the counties within the watch in
its area of responsibility. As the event unfolds, the WCN products are
issued by the WFO to clear counties from each watch until the watch has
expired. The WCN may also be used to add counties to the watch and also
extend it in time.

**3.2.1.5 Public Warnings.**

**3.2.1.5.1 WFO.** Each WFO issues severe thunderstorm and tornado
warnings (see Appendix A for an example of a severe thunderstorm
warninig), which encompass severe weather expected within an hour of the
warning issuance (warnings can be issued for a shorter period). Warnings
are often updated with a severe weather statement while the warning is
in effect, and a severe weather statement will indicate when a warning
has expired. The warnings use a 'bullet' format to highlight the most
important warning parameters, such as type of warning, when a warning is
in effect, basis for the warning, and an optional pathcast forecasting
the times and locations of the severe weather.

**3.2.1.5.2 Convective SIGMETs.** The AWC issues Convective SIGMET
bulletins both hourly, at 55 minutes past the hour, and as required over
the conterminous U.S. and adjacent coastal waters (see Appendix A for an
example of a Convective SIGMET ) for areas greater than 3000 square
miles. Negative bulletins are issued if none of the criteria specified
in Chapter 2 are met. Convective SIGMETs alert in-flight interests for:

-   tornadoes

-   lines of thunderstorms

-   embedded thunderstorms of any intensity

-   active thunderstorms affecting at least 3000 square miles

-   severe thunderstorms with hail greater than 3/4\" diameter

or greater or winds 50 knots or greater

**3.2.1.5.3 National Convective Weather Forecast (NCWF) Product**. The
NWCF supplements the convective airmen's meteorological information
(AIRMETs) and SIGMET products. The NCWF product provides forecasts of
significant thunderstorm locations one hour in the future, and is
updated every five minutes. This product is available via Internet from
AWC's operational server: http://www.awc-kc.noaa.gov/.

**3.2.1.5.4 Center Weather Service Unit (CWSU).** The CWSU prepares the
Center Weather Advisory message for the aviation community which can
include severe weather convective SIGMETs for areas less than 3000
square miles.

**3.2.1.5.5 Special Marine Warnings (SMW).** The WFOs issue SMWs for
hazardous over-water events of short duration (up to 2 hours) and for
events inadequately covered by existing marine warnings and forecasts
(see Appendix A for an example of an SMW) .These events can include
convective activity, squalls or wind shift lines, waterspouts, cold air
funnels and other localized short-lived phenomena.

**3.3 [DOD Watch/Warning Procedures.]{.underline}**

**3.3.1 USAF.** The Air Force provides weather warning support for both
the Air Force and Army, including active and reserve components. All
sites receive watches and warnings for thunderstorms, severe
thunderstorms, tornadic thunderstorms, and lightning strikes. Warning
lead-times are standardized to the greatest extent possible; specific
mission needs may drive non-standard lead times and criteria.
Standardized lead times are 90 minutes for moderate thunderstorms (those
with with ½-inch hail and/or 35-49-knot winds associated), 2 hours for
severe thunderstorms, 15 minutes for tornadoes, and 30 minutes (prior to
a thunderstorm within 5 nm of the installation or airfield) for
lightning watches. Lightning warnings are issued when lightning is
observed within 5 nm of the installation.

**3.3.1.1** **Operational Weather Squadrons (OWSs).** The Air Force OWSs
at Barksdale AFB, LA; Scott AFB, IL; Davis Monthan AFB, AZ; and Hickam
AFB, HI. forecast services for designated regions of the U.S. These
squadrons provide weather warning support for Active Duty, Guard, and
Reserve Air Force and Army installations within their areas of
responsibility. Whenever possible CONUS OWSs will be included on severe
weather conference calls between SPC and the WFOs prior to issuance of a
severe weather watch. Figure 3-1 graphically represents relation between
principal CONUS forecast centers in case of severe weather. Routine
collaboration between military and civilian forecast centers will ensure
forecast consistency and provide full benefit of meteorological
expertise.

![](media/image1.wmf){width="6.011805555555555in"
height="4.503472222222222in"}

**Figure 3-1 Severe Weather Product Generation**

**3.3.1.2 Local Unit Warning**. At those locations where a USAF
forecaster is on duty, the forecaster may issue warnings and advisories,
mainly for observed criteria. The criteria and any lead-times for
warnings are established locally, based on customer needs.

**3.3.2.** **USN and USMC.** Navy Meteorology and Oceanography (METOC)
Command Centers and Marine Corps weather activities are responsible for
the timely dissemination of hazardous or destructive weather warnings
via designated area commands and activities. If USN and USMC weather
activities are not available, full use should be made of storm warning
information disseminated by other agencies (e.g. NWS, USAF, and local
foreign meteorological services). In the U.S., NWS Bulletins are often
heard first over television or radio, therefore prior familiarity with
their terminology will enhance their value and avoid confusion when
Warning Conditions are normally set by the local area commanders. For
severe local storms, Conditions II and I are used to avoid or minimize
loss and damage due to destructive weather phenomena and are based on
all available weather information.

**3.3.2.1 Conditions of** **Readiness**

+--------------------+-------------------------------------------------+
| TROPICAL CYCLONE,  |                                                 |
| SUB-TROPICAL,      |                                                 |
| EXTRA-TROPICAL     |                                                 |
| WIND STORMS        |                                                 |
|                    |                                                 |
| (Issue using gale, |                                                 |
| storm, tropical    |                                                 |
| storm, or          |                                                 |
| hurricane/typhoon  |                                                 |
| to indicate force  |                                                 |
| of destructive     |                                                 |
| winds.)            |                                                 |
+--------------------+-------------------------------------------------+
| Condition IV       | Trend indicates a possible threat of            |
|                    | destructive winds of the force indicated within |
|                    | 72 hours. Review hazardous and destructive      |
|                    | weather implementation plans, as established by |
|                    | local regulations.                              |
+--------------------+-------------------------------------------------+
| Condition III      | Destructive winds of the force indicated are    |
|                    | possibly within 48 hours. Take preliminary      |
|                    | precautions.                                    |
+--------------------+-------------------------------------------------+
| Condition II       | Destructive winds of the force indicated are    |
|                    | anticipated within 24 hours. Take precautions   |
|                    | that will permit establishment of an            |
|                    | appropriate state of readiness on short notice  |
+--------------------+-------------------------------------------------+
| Condition I        | Destructive winds of the force indicated are    |
|                    | occurring or anticipated within 12 hours. Take  |
|                    | final precautions as prescribed.                |
+--------------------+-------------------------------------------------+

Statements setting Conditions of Readiness may be amplified by
additional information. The forecast wind values may be different that
the threshold values in enclosure (1) to reflect best possible forecast
information. Examples:

"Set Gale Condition II. Destructive winds of 35 to 40 knots are
anticipated within 24 hours."

"Set Tropical Storm Condition III. Destructive winds of 50 knots or
greater are possible within 48 hours."

"Set Hurricane Condition I. Destructive winds of 64 knots or greater are
anticipated within 12 hours."

**3.4 [Backup Operations for SPC and AWC.]{.underline}** The SPC, AWC
and AFWA have agreed that the AFWA will provide limited backup
capability for both SPC and AWC. Appendix C contains the Memorandum of
Agreement that covers these backup arrangements, specifying the severe
weather forecast and aviation products that AFWA will produce when
required to backup either SPC or AWC. The coordination channel for
backup plans and procedures and for exchange of data and products among
SPC, AWC and AFWA shall be between the Commander, AFWA, and the
Director, SPC or AWC, as appropriate. Unresolved differences will be
worked out between the Director, NCEP and the Commander, AFWA.

SPC AC 161603

DAY 1 CONVECTIVE OUTLOOK

NWS MKCSWODY2

ACUS2 KMKC 171714

STORM PREDICTION CENTER NORMAN OK

1103 AM CDT TUE OCT 16 2007

VALID 161630Z - 171200Z

\... DAY 2 CONVECTIVE OUTLOOK\...REF AFOS NMCGPH98O.

VALID 231200Z - 241200Z

THERE IS A SLGT RISK OF SVR TSTMS PARTS OF SOUTHERN HIGHTO THE RIGHT OF
A LINE FROM PLAINS\...

\...SYNOPSIS\...

SURFACE/UPPER LOW WILL MOVE NNEWD ACROSS MN THIS AFTERNOON AND

WEAKEN AS A POWERFUL POLAR JET AND NEGATIVELY TILTED TROUGH RAPIDLY

DEVELOPS EWD ACROSS SWRN U.S. AT THE SURFACE OLD FRONTAL ZONE

ACROSS LOWER MS VLY/SRN PLAINS WILL REDEVELOP NWD ACROSS CENTRAL

PLAINS INTO LOWER MO VALLEY TONIGHT IN RESPONSE TO LEE CYCLOGENESIS

CENTRAL HIGH PLAINS. TROPICAL LIKE AIR MASS IN PLACE S TX WILL

ACCELERATE NWD THRU SRN INTO CENTRAL HI PLAINS THIS FORECAST PERIOD

AS 40-50KT SLY LOW LEVEL JET KICKS IN TONIGHT.

\...ERN WI INTO NRN IND AND WRN OH\...

CURRENT CLOUD COVER ACROSS THIS AREA EXPECTED TO THIN AS MID LEVEL

DRYING SPREADS NEWD TO E OF UPPER LOW OVER SRN MN. ALTHOUGH OVERALL

SYSTEM IS WEAKENING\...SUFFICIENT LOW LEVEL MOISTURE TO SUPPORT

SURFACE BASED THUNDERSTORM DEVELOPMENT AS TEMPERATURES WARM TO NEAR

70F. WITH 30-40KT OF SHEAR AND POTENTIALLY MLCAPES TO 500 J/KG IN

AREAS OF GREATEST SURFACE HEATING\...A FEW STRONG/SEVERE

THUNDERSTORMS ARE POSSIBLE BY MID AFTERNOON. ANY SEVERE THREAT

SHOULD QUICKLY END AFTER SUNSET GIVEN THE OVERALL MARGINAL SETUP AND

THE WEAKENING OF THE UPPER SYSTEM.

\...SRN PLAINS\...

COMBINATION OF INCREASING LARGE SCALE ASCENT/WAA AND MOISTURE INFLUX

BENEATH EML PLUME SWEEPING E FROM THE SRN PLATEAU SHOULD LEAD TO

TSTM DEVELOPMENT ALONG NW FRINGE OF MOIST AXIS\...POSSIBLY AS EARLY

AS THIS EVENING IN V35 ESE GAG END FSM PBF MLU LFK AUS 50 NNW SAT ABI
LTS 35 ESE GAG.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM PSX SAT ABI BGS CNM

4CR RTN LIC SNY MHN OFK CID SPI 25 SSE MDH DYR GWO HEZ 25 S LCH.

UPPER LOW OVER AZ IS FORECAST TO MOVE EASTWARD ON THURSDAY ACROSS

THE CENTRAL PLAINS AND INTO THE UPPER MS VALLEY. ASSOCIATED

SURFACE LOW SHOULD TRACK ACROSS OK DURING THE DAY\...WITH WARM

FRONT EXTENDING SOUTHEASTWARD INTO LA. MEANWHILE\...SURFACE DRYLINE

WILL MIX EASTWARD INTO NORTHEAST TX BY AFTERNOON. THE TRIPLE-POINT

OF THE TX/NM BORDER. THIS ACTIVITY SHOULD

INCREASE IN COVERAGEDRYLINE AND SPREAD NE ALONG DEVELOPING WARM FRONT
INTO

OK TONIGHT/EARLY WEDNESDAY AS UPR SYSTEM CONTINUES RAPIDLY EWD.

GIVEN INCREASING DEGREE OF INSTABILITY /MUCAPE TO 1000 J PER KG/

WITH STRENGTHENING ASCENT AND DEEP SHEAR\...SETUP MAY SUPPORT A FEW

SUSTAINED STORMS/POSSIBLE SUPERCELLS WITH HAIL. AND\...GIVEN BE THE

TIME OF DAY AND CHARACTER OF FORCING\...MOST OF THIS ACTIVITY LIKELY

WILL BE SLIGHTLY ELEVATED. A LIMITED POTENTIAL

WILL\...HOWEVER\...EXIST PRIMARY FOCUS FOR A FEW SFC-OR NEAR SFC-BASED
STORMS THAT SEVERE MAY POSE A BRIEF TORNADO THREAT GIVEN EXPECTED
EFFECTIVE SRH VALUES

OF 250-350 THUNDERSTORM THREAT ON THURSDAY.

\...NORTH-CENTRAL TX THURSDAY MORNING\...

SCATTERED THUNDERSTORMS ARE EXPECTED TO BE ONGOING AT THE

BEGINNING OF THE PERIOD OVER CENTRAL TX AND SOUTHERN OK. STRONG

WIND FIELDS AND RELATIVELY STEEP LAPSE RATES MAY SUPPORT ISOLATED

STRONG/SEVERE STORMS WITH DAMAGING WINDS AND HAIL. THIS ACTIVITY

SHOULD SLOWLY WEAKEN THROUGH THE DAY AS IT MOVES NORTHEASTWARD

WITH WARM FRONT ACROSS OK INTO AR.

\...NORTHEAST TX AND SOUTHEAST OK\...

AMPLE MOISTURE IS IN PLACE ACROSS CENTRAL/ SOUTH TX WHICH SHOULD

SPREAD RAPIDLY NORTHWARD. CLOUDINESS WILL LIMIT HEATING\...BUT

FORECAST SOUNDINGS IN NORTHEAST TX SUGGEST THAT CAPE VALUES OF

1000-1500 J/KG ARE LIKELY. SHEAR PROFILES WILL ALSO BE QUITE FAVORABLE
IN

THIS REGION WITH 6KM SHEAR OVER 50 KNOTS AND 3KM HELICITY VALUES

AROUND 200 M2/S2. ISOLATED SUPERCELL DEVELOPMENT MAY OCCUR IN THIS

..HALES/KIS.. 10/16/2007

**Example of an SPC Severe Weather text Outlook for Day One**

MESOSCALE DISCUSSION 0077

NWS STORM PREDICTION CENTER NORMAN OK

0142 PM CST SAT JAN 19 2008

AREAS AFFECTED\...CENTRAL/NRN FL PENINSULA

CONCERNING\...SEVERE POTENTIAL\...WATCH POSSIBLE

VALID 191942Z - 192045Z

BOUNDARY LAYER AIRMASS IS RECOVERING NWD ACROSS THE FL PENINSULA AS WARM
FRONT RETREATS IN ADVANCE OF APPROACHING COLD FRONT. LATEST

SFC ANALYSIS INDICATES SFC WINDS ARE VEERING ACROSS THE PENINSULA

WITH UPPER 70S TEMPERATURES AND UPPER 60S DEW POINTS IMMEDIATELY

SOUTH OF THE WARM FRONT EXTENDING FROM PASCO COUNTY TO JUST NORTH OF TPA
TO BREVARD COUNTY. LATEST THINKING IS THIS BOUNDARY WILL LIFT INTO LEVY
COUNTY\...STRETCHING TO ST. JOHNS COUNTY PRIOR TO 00Z WHERE EXPECTED SFC
LOW SHOULD TRACK EARLY THIS EVENING.

THUNDERSTORMS OF NOTABLE INTENSITY\...A FEW OF WHICH APPEAR
SUPERCELLULAR\...ARE DEVELOPING/ADVANCING NEWD AHEAD OF COLD FRONT. THIS
ACTIVITY SHOULD APPROACH THE WRN FL PENINSULA BY 21Z. GIVEN

THE AIRMASS RECOVERY IT SEEMS PLAUSIBLE THAT A FEW OF THESE STORMS

WILL PRODUCE ISOLATED SEVERE WIND GUSTS\...OR PERHAPS A TORNADO.
STRONGEST AND MORE FOCUSED SHEAR WILL BE ALONG THE WARM FRONT\...AND

THIS IS THE MOST LIKELY AXIS FOR TORNADOES.

**Example of an SPC Mesoscale Discussion for Severe Weather**

WWUS9 KMKC 251710

MKC WW 251710

KSZ000-260100-

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 737183

NWS STORM PREDICTION CENTER NORMAN OK

1030 AM CST SUN NOV 25 2007

> NATIONAL WEATHER SERVICE NORMAN OK
>
> 1210 PM CDT FRI FEB 25 2000

.A\...THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

SOUTH CENTRAL AND SOUTHEAST LOUISIANA

COASTAL WATERS

PARTS OF CENTRAL AND EASTERN KANSAS

EFFECTIVE THIS SUNDAY MORNING AND FRIDAY AFTERNOON FROM 1030 AMAND
EVENING UNTIL 500 800 PM CSTCDT.

TORNADOES\...HAIL TO 0.5 INCH IN DIAMETER\...THUNDERSTORM WIND

GUSTS TO 70 MPH

THIS IS A PARTICULARLY DANGEROUS SITUATION WITH THE POSSIBILITY OF VERY
DAMAGING TORNADOES. ALSO LARGE HAIL\...DANGEROUS LIGHTNING ARE POSSIBLE
IN THESE\...AND DAMAGING THUNDERSTORM WINDS CAN BE EXPECTED.

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 65 STATUTE

MILES NORTHEAST AND SOUTHWEST OF A LINE FROM 4045 MILES WEST NORTHWEST
OF

INTRACOASTAL CITY LOUISIANA TO 40 MILES EAST SOUTHEAST OF NEW
ORLEANSMEDICINE LODGE KANSAS TO 45 MILES NORTHEAST OF CONCORDIA KANSAS.

LOUISIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).

REMEMBER\...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

FAVOR TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS.

DISCUSSION\...A WARM FRONT WILL LIFT SLOWLY NWD ACROSS SRN LA
THROUGHWARM MOIST UNSTABLE AIR MASS IN PLACE OVER WESTERN

THE AFTERNOON IN ADVANCE OF A MID LEVEL LOW OVER TX\...AND A SURFACE

LOW DEVELOPING NEWD TOWARD SW LA. DESPITE WIDESPREAD CLOUDS AND

LIMITED SURFACE HEATING\...BOUNDARY LAYER DEWPOINTS IN THE KANSAS WITH
MUCAPES NOW AROUND 2000 TO 3000 J/KG. UPPER 60S

FORCING WILL CONTRIBUTE TO SBCAPE VALUES OF 500-1000 J/KG THIS AFTERNOON

ALONG AND S OF THE WARM FRONT. VERTICAL SHEAR WILL BE MAXIMIZED

ALONG THE BOUNDARY\...WHERE SUPERCELLS AND A TORNADO OR TWO WILL BE

POSSIBLE. OTHERWISE\...ISOLATED DAMAGING WINDS CAN BE EXPECTED WITH

THE MOST INTENSE STORMS.

INCREASE AS UPPER TROUGH APPROACHES REGION. 30 TO 40 KT LOW LEVEL JET
UNDER 50 TO 60 KT MID LEVEL FLOW WILL RESULT IN FAVORABLE SHEAR FOR AT
LEAST ISOLATED DESTRUCTIVE TORNADOES AND SCATTERED LARGE HAIL AND
DAMAGING DOWNBURSTS.

AVIATION\...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 0.5 INCH.3 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 6075 KNOTS. A FEW CUMULONIMBICUMULONIMBUS WITH MAXIMUM
TOPS TO 600. MEAN WIND VECTOR 23040.

500\. MEAN STORM MOTION VECTOR 24025.

\...THOMPSON

**Example of an NWS Public Watch Bulletin issued by SPC**

WOUS64 KWNS 251626

WOU7

BULLETIN - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH OUTLINE UPDATE FOR WT 737

NWS STORM PREDICTION CENTER NORMAN OK

1030 AM CST SUN NOV 25 2007

TORNADO WATCH 737 IS IN EFFECT UNTIL 500 PM CST FOR THE

FOLLOWING LOCATIONS

LAC001-005-007-023-033-039-045-047-051-053-055-057-063-071-075-

077-087-089-093-095-097-099-101-109-113-121-252300-

/O.NEW.KWNS.TO.A.0737.071125T1630Z-071125T2300Z/

LA

. LOUISIANA PARISHES INCLUDED ARE

ACADIA ASCENSION ASSUMPTION

CAMERON EAST BATON ROUGE EVANGELINE

IBERIA IBERVILLE JEFFERSON

JEFFERSON DAVIS LAFAYETTE LAFOURCHE

LIVINGSTON ORLEANS PLAQUEMINES

POINTE COUPEE ST. BERNARD ST. CHARLES

ST. JAMES ST. JOHN THE BAPTISTST. LANDRY

ST. MARTIN ST. MARY TERREBONNE

VERMILION WEST BATON ROUGE

GMZ452-455-530-550-252300-

/O.NEW.KWNS.TO.A.0737.071125T1630Z-071125T2300Z/

CW

. ADJACENT COASTAL WATERS INCLUDED ARE

COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA OUT 20 NM

COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO INTRACOASTAL CITY

LA OUT 20 NM

LAKE PONTCHARTRAIN AND LAKE MAUREPAS

COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER

TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM

ATTN\...WFO\...LCH\...LIX\...

**Example of a redefined NWS Public Watch Outline Update (WOU)**
**bulletin issued by SPC**

WOUS20 KWNS 252240

WWASPC

SPC WW-A 252240

NYZ000-OHZ000-PAZ000-LEZ000-LOZ000-092300-

STATUS REPORT ON WW 737

THE SEVERE WEATHER THREAT CONTINUES TO THE RIGHT OF A LINE FROM 50 SW
HUM TO 30 NW BE.

..KERR..11/25/07

ATTN\...WFO\...LCH\...LIX\...

&&

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS

LAC075-252300-

LA

. LOUISIANA PARISHES INCLUDED ARE

PLAQUEMINES

GMZ550-252300

CW

. ADJACENT COASTAL WATERS INCLUDED ARE

COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISIPPI RIVER

TO LOWER ATCHAFALAYA RIVER LA OUT 20 NM

\$\$

THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER

TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON

COUNTIES\... INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE

THUNDERSTORM AND TORNADO WATCHES.

**Example of a NWS Watch Status Message issued by SPC**

SAW7

WW 737 TORNADO LA CW 251630Z - 252300Z

AXIS..50 STATUTE MILES NORTH AND SOUTH OF LINE..

40WNW 7R4/INTRACOASTAL CITY LA/ - 40SE MSY/NEW ORLEANS LA/

..AVIATION COORDS.. 45NM N/S /21ESE LCH - 30NE LEV/

HAIL SURFACE AND ALOFT..0.5 INCH. WIND GUSTS..60 KNOTS.

MAX TOPS TO 500. MEAN STORM MOTION VECTOR 24025.

LAT\...LON 30719275 30308977 28878977 29289275

THIS IS AN APPROXIMATION TO THE WATCH AREA. FOR A

COMPLETE DEPICTION OF THE WATCH SEE WOUS64 KWNS

FOR WOU7.

**Example of a NWS Aviation Watch bulletin issued by SPC**

RDUTORMHX

TTAA00 KMHX 061730

NCC013-147-061815-

BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC

130 PM EDT TUE MAY 6 1997

THE NATIONAL WEATHER SERVICE IN NEWPORT/MOREHEAD CITY

HAS ISSUED A

\* TORNADO WARNING FOR\...

PITT COUNTY IN EASTERN NORTH CAROLINA

BEAUFORT COUNTY IN EASTERN NORTH CAROLINA

\* UNTIL 215 PM EDT

\* AT 130 PM EDT\...NATIONAL WEATHER SERVICE DOPPLER

RADAR INDICATED A TORNADO 5 MILES NORTH OF

WINTERVILLE\...MOVING TO THE EAST AT 20 MPH.

\* THE TORNADO IS EXPECTED TO BE NEAR\...

SIMPSON AT 140 PM EDT

GRIMESLAND AT 145 PM EDT

WASHINGTON AT 155 PM EDT

PERSONS IN OR CLOSE TO THE WARNED AREA\...TAKE SHELTER IN

A BASEMENT OR SMALL INTERIOR ROOM\...AWAY FROM WINDOWS.

**Example of a NWS WFO Warning bulletin in the format used for tornado,
severe thunderstorm, and flash flood warnings**

MKCC WST 231855

CONVECTIVE SIGMET 20C

VALID UNTIL 2055Z

ND SD

FROM 90W MOT-GFK-ABR-90W MOT

INTSFYG AREA SVR TSTMS MOVG FROM 2445. TOPS ABV 450. WIND GUSTS TO 60 KT

RPRTD.

TORNADOES\...HAIL TO 2 IN\...WIN GUSTS TO 65 KT PSBL ND PTN.

CONVECTIVE SIGMET 21C

VALID UNTIL 2055Z

TX

50SE CDS

ISOLD SVR TSTM D30 MOVG FROM 2420. TOP ABV 450.

HAIL TO 1 ½ IN\...WIND GUSTS TO 60 KT RPRTD.

HAIL TO 2 IN\...WIND GSUST TO 65 KT PSBL.

OUTLOOK VALID 232055-230055

AREA 1\...FROM INL-MSP-ABR-MOT-INL

SVR TSTMS CONT TO DVLP IN AREA OVER ND. AREA IS EXPCD TO

RMN SVR AND SPREAD INTO MN AS STG PVA MOVES OVR VERY

UNSTBL AMS CHARACTERIZED BY -12 LIFTED INDEX.

AREA 2\...FROM CDS-DFW-LRD-ELP-CDS

ISOLD STG TSTMS WILL DVLP OVR SWRN AND WRN TX THRUT FCST

PD AS UPR LVL TROF MOVES NEWD OVR VERY UNSTBL AMS.

LIFTED INDEX RMNS IN THE -8 TO -10 RANGE. DRY LINE WILL BE THE FOCUS OF
TSTM

DVLPMT.

**Example of a NWS Convective SIGMET issued by AWC**

WMUS1 KLAX 062150

SMWLAX

PZZ650-062300-

BULLETIN - EAS ACTIVATION REQUESTED

SPECIAL MARINE WARNING

NATIONAL WEATHER SERVICE OXNARD CA

250 PM PDT WED AUG 6 1997

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

\* SPECIAL MARINE WARNING FOR\...

THE EAST SANTA BARBARA CHANNEL

FROM PT CONCEPTION TO PT MUGU INCLUDING SANTA CRUZ ISLAND

\* UNTIL 400 PM PDT

\* AT 245 PM PDT\...NATIONAL WEATHER SERVICE DOPPLER RADAR

INDICATED STRONG THUNDERSTORMS DEVELOPING BETWEEN OXNARD

AND SANTA CRUZ ISLAND\...MOVING TO THE NORTHWEST AT 20 MPH.

\* THE THUNDERSTORM THREAT WILL BE GREATEST FROM\...

OXNARD TO EAST SANTA CRUZ ISLAND BY 300 PM PDT WEST SANTA

CRUZ ISLAND TO SANTA BARBARA HARBOR BY 330 PM PDT

THESE THUNDERSTORMS WILL PRODUCE WIND GUSTS TO 40

KNOTS\...ROUGH SEAS AND NEAR ZERO VISIBILITY. BOATERS IN

AST SANTA BARBARA CHANNEL SHOULD TRY TO SEEK SAFE HARBOR.

**Example of a NWS Special Marine Warning bulletin issued by WFOs**