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911 

WWUS20 KWNS 280243

SEL5

SPC WW 280243

ALZ000-MSZ000-280700-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 245

NWS STORM PREDICTION CENTER NORMAN OK

940 PM CDT WED APR 27 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       ALABAMA

       FAR SOUTHEAST MISSISSIPPI



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 940 PM

UNTIL 200 AM CDT.



TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND

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

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE

MILES EAST AND WEST OF A LINE FROM GADSDEN ALABAMA TO 105 MILES

SOUTHWEST OF SELMA ALABAMA.  FOR A COMPLETE DEPICTION OF THE

WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 235...WW 238...WW

239...WW 240...WW 241...WW 242...WW 243...WW 244...



DISCUSSION...WHILE STRONG MIDLEVEL VORTICITY MAXIMUM IS NOW

BEGINNING TO LIFT NEWD AWAY FROM THE REGION...LOW-LEVEL CONVERGENCE

SHOULD SERVE TO MAINTAIN TSTMS ALONG COLD FRONT PROGRESSING EWD

ACROSS WW AREA.  AMBIENT AIR MASS REMAINS VERY MOIST AND MODERATELY

UNSTABLE WITH MLCAPE VALUES OF 1500-3000 J/KG.  WHEN COUPLED WITH

EFFECTIVE SRH VALUES OF 300-500 M2/S2...ENVIRONMENT REMAINS

SUPPORTIVE OF SUPERCELLS CAPABLE OF TORNADOES...LARGE HAIL AND

DAMAGING WINDS WINDS.



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

SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

500. MEAN STORM MOTION VECTOR 24040.





...MEAD

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