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000 

WWUS20 KWNS 302052

SEL4

SPC WW 302052

FLZ000-CWZ000-310500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 874

NWS STORM PREDICTION CENTER NORMAN OK

450 PM EDT SAT AUG 30 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHWEST FLORIDA AND THE FLORIDA KEYS

       COASTAL WATERS



EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 450 PM

UNTIL 100 AM EDT.



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 25 STATUTE

MILES EITHER SIDE OF A LINE FROM 20 MILES EAST NORTHEAST OF

MARATHON FLORIDA TO 25 MILES WEST OF KEY WEST FLORIDA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU4).



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.



DISCUSSION...THE OUTER RAINBANDS OF HURRICANE GUSTAV WILL CONTINUE

TO OVERSPREAD THE KEYS AND SW FL THROUGH TONIGHT.  THE EYW VWP HAS

SHOWN A GRADUAL INCREASE IN LOW-LEVEL SHEAR THROUGH THE

AFTERNOON...WHILE CELLULAR CONVECTION CONTINUES TO DEVELOP IN

SEVERAL BANDS APPROACHING THE KEYS AND SW FL.  THE THREAT FOR

SUPERCELLS WITH TORNADOES/ WATERSPOUTS WILL LIKEWISE INCREASE

THROUGH THE EVENING INTO TONIGHT AS GUSTAV MAKES ITS CLOSEST

APPROACH THE TO FL KEYS LATE TONIGHT.



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

500. MEAN STORM MOTION VECTOR 11040.





...THOMPSON

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