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WWUS20 KWNS 181221 CCA

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 804...CORRECTED

NWS STORM PREDICTION CENTER NORMAN OK

745 AM EST FRI DEC 18 2009



CORRECTED FOR TIME ZONE



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTH FLORIDA AND THE FLORIDA KEYS

       COASTAL WATERS



EFFECTIVE THIS FRIDAY MORNING AND AFTERNOON FROM 745 AM UNTIL 100

PM EST.



TORNADOES...HAIL TO 2 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 80 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 40 MILES SOUTH OF NAPLES

FLORIDA TO 20 MILES SOUTHEAST OF WEST PALM BEACH 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...A BROKEN BAND OF THUNDERSTORMS...SOME OF WHICH ARE

SUPERCELLS...WILL CONTINUE TO SPREAD NWD/NEWD ACROSS S FL AS A

SURFACE LOW DEEPENS ACROSS THE NE GULF OF MEXICO.  A GRADUAL

INCREASE IN LOW-MID LEVEL WIND SPEEDS AND VERTICAL SHEAR...ALONG

WITH LOW-LEVEL MOISTENING AND SOME SURFACE HEATING IN SMALL CLOUD

BREAKS...WILL CONTRIBUTE TO AN INCREASING THREAT FOR SUPERCELLS AND

A COUPLE OF TORNADOES THROUGH THE MORNING.



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

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

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

500. MEAN STORM MOTION VECTOR 22020.





...THOMPSON

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