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228 

WWUS20 KWNS 221603

SEL9

SPC WW 221603

ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-222300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 899

NWS STORM PREDICTION CENTER NORMAN OK

1000 AM CST THU DEC 22 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       ALABAMA

       WESTERN FLORIDA PANHANDLE

       FAR SOUTHEAST LOUISIANA

       SOUTHEAST MISSISSIPPI

       COASTAL WATERS



EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 1000 AM UNTIL

500 PM CST.



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

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE

MILES EAST AND WEST OF A LINE FROM 25 MILES EAST OF GULFPORT

MISSISSIPPI TO 10 MILES NORTH OF GADSDEN ALABAMA.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU9).



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

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.



OTHER WATCH INFORMATION...CONTINUE...WW 898...



DISCUSSION...CONVECTIVE BAND ALONG COLD FRONT FROM NEAR JAN TO W OF

NEW ORLEANS IS EXPECTED TO INTENSIFY TODAY WHILE MOVING EWD WITH

ADDITIONAL DOWNSTREAM STORM DEVELOPMENT ANTICIPATED WITHIN THE OPEN

WARM SECTOR.  LATEST VISIBLE SATELLITE SHOWS BREAKS IN THE CLOUDS

ACROSS PARTS OF SRN AL...WHICH WHEN COUPLED WITH BOUNDARY LAYER

DEWPOINTS IN THE MID 60S WILL YIELD AFTERNOON MLCAPE VALUES OF

AROUND 1000 J/KG.  THIS INSTABILITY WILL COINCIDE WITH A KINEMATIC

ENVIRONMENT FEATURING 0-1 KM SRH OF 150-300 M2/S2 AND EFFECTIVE BULK

SHEAR OF 40-50+ KT.  AS SUCH...GIVEN SETUP WILL SUPPORT SUPERCELL

AND BOW ECHO STORM MODES WITH ATTENDANT RISKS FOR A FEW TORNADOES

AND DAMAGING WINDS.



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

SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

400. MEAN STORM MOTION VECTOR 22035.





...MEAD

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