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WWUS20 KWNS 281858

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LAZ000-MSZ000-CWZ000-290100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 857

NWS STORM PREDICTION CENTER NORMAN OK

200 PM CDT WED SEP 28 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHEAST LOUISIANA

       A SMALL PART OF SOUTHERN MISSISSIPPI

       COASTAL WATERS



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 200 PM UNTIL

800 PM CDT.



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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTHWEST

OF BATON ROUGE LOUISIANA TO 50 MILES EAST SOUTHEAST OF GULFPORT

MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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.



DISCUSSION...THUNDERSTORMS WILL CONTINUE TO INCREASE IN

COVERAGE/INTENSITY ALONG A FRONT/OUTFLOW BOUNDARY FROM SRN MS INTO

SE LA...AND THE STORMS WILL SPREAD SEWD THROUGH THE AFTERNOON.

THOUGH VERTICAL SHEAR IS WEAK...STRONG INSTABILITY WILL PROMOTE A

RISK OF DAMAGING DOWNBURSTS AND LARGE HAIL WITH THE STRONGEST

STORMS.



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 600. MEAN STORM

MOTION VECTOR 29020.





...THOMPSON

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