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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 139

NWS STORM PREDICTION CENTER NORMAN OK

1255 PM CDT WED APR 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       DEEP SOUTH TEXAS AND THE COASTAL PLAIN

       COASTAL WATERS



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1255 PM UNTIL

800 PM CDT.



HAIL TO 2 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 45

STATUTE MILES EITHER SIDE OF A LINE FROM 25 MILES NORTH NORTHEAST

OF ANGLETON TEXAS TO 35 MILES NORTHWEST OF MCALLEN TEXAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU9).



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...SUPERCELLS HAVE EVOLVED TODAY NEAR AN OUTFLOW BOUNDARY

SW OF HOU WITH ADDITIONAL TSTMS ANTICIPATED SWWD ALONG SYNOPTIC

FRONT AND DEVELOPING SEA BREEZE CIRCULATION.  MODIFICATION OF 12Z

BRO/CRP SOUNDINGS FOR CURRENT SURFACE CONDITIONS INDICATES THAT AIR

MASS HAS BECOME WEAKLY CAPPED WITH MLCAPE OF 3000-3500 J/KG.

MOREOVER...HOU VAD SHOWS LIGHT SELY WINDS VEERING TO 50 KT AT 6 KM

AGL...INDICATIVE OF A CONTINUED SUPERCELL THREAT.  LARGE HAIL AND

DAMAGING WIND GUSTS WILL BE THE PRIMARY HAZARDS WITH THESE STORMS.



AVIATION...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 550. MEAN STORM

MOTION VECTOR 30010.





...MEAD

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