

997 

WWUS20 KWNS 041707

SEL0

SPC WW 041707

FLZ000-GAZ000-SCZ000-042300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 240

NWS STORM PREDICTION CENTER NORMAN OK

110 PM EDT MON MAY 4 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN FLORIDA

       SOUTHERN GEORGIA

       SOUTHERN SOUTH CAROLINA



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 110 PM UNTIL 700

PM EDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM MARIANNA FLORIDA TO

30 MILES SOUTH SOUTHEAST OF SAVANNAH GEORGIA.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU0).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 238...WW 239...



DISCUSSION...COLD POOL ASSOCIATED WITH SRN AL/WRN FL PANHANDLE MCS

APPEARS TO BE GROWING AND SUPPORTING ENHANCED UPDRAFT DEVELOPMENT

ALONG LEADING EDGE. RESULTING BOWING STRUCTURE HAS PICKED UP FORWARD

SPEED AND SHOULD MOVE INTO WRN PORTIONS OF THIS WATCH WITHIN THE

HOUR. ADDITIONAL VIGOROUS STORM DEVELOPMENT IS ANTICIPATED AS LIFT

ASSOCIATED WITH THE MCV/MCS DEVELOPS EWD ACROSS SRN GA THROUGH THE

AFTERNOON. DEEP-LAYER EFFECTIVE SHEAR ON THE ORDER OF 30KT

COINCIDENT WITH CONVECTIVE DEVELOPMENT SHOULD CONTRIBUTE TO STORM

ORGANIZATION WITHIN MODESTLY UNSTABLE AIR MASS CHARACTERIZED BY

MLCAPE 800-1200 J/KG. EXPECT PRIMARY THREAT WILL BE DAMAGING WINDS

ALTHOUGH HAIL WILL ALSO BE POSSIBLE WITH STRONGER AND MORE

PERSISTENT UPDRAFTS.



AVIATION...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 27035.





...CARBIN

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