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WWUS20 KWNS 090809

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 4

NWS STORM PREDICTION CENTER NORMAN OK

210 AM CST SUN JAN 9 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       A SMALL PART OF SOUTH CENTRAL TEXAS AND THE MIDDLE TX COAST

       COASTAL WATERS



EFFECTIVE THIS SUNDAY MORNING FROM 210 AM UNTIL 700 AM CST.



HAIL TO 1 INCH 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 35

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST

SOUTHWEST OF ALICE TEXAS TO 65 MILES EAST NORTHEAST OF CORPUS

CHRISTI TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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...AN ORGANIZED QLCS WILL MOVE EWD/ENEWD ACROSS S TX TO

THE MIDDLE TX COAST IN ADVANCE OF AN EJECTING MIDLEVEL TROUGH AND

ASSOCIATED SURFACE LOW.  THE MAIN SEVERE THREAT CORRIDOR WILL BE

ALONG THE WARM FRONT/INSTABILITY GRADIENT WHERE NEAR SURFACE-BASED

INSTABILITY WILL COINCIDE WITH STRONG VERTICAL SHEAR.  DAMAGING

WINDS WITH BOWING SEGMENTS SHOULD BE THE MAIN THREAT...THOUGH AN

ISOLATED TORNADO CANNOT BE RULED OUT WHERE STORMS INTERACT WITH THE

WARM FRONT...WHICH WILL MOVE CLOSE TO CRP BEFORE THE CONVECTION

REACHES THE COAST AROUND 11Z.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM MOTION

VECTOR 25040.





...THOMPSON

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