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WWUS20 KWNS 301828

SEL2

SPC WW 301828

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 202

NWS STORM PREDICTION CENTER NORMAN OK

130 PM CDT MON APR 30 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTH CENTRAL AND SOUTHEAST TEXAS



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 130 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 45

STATUTE MILES EAST AND WEST OF A LINE FROM 95 MILES NORTH

NORTHEAST OF VICTORIA TEXAS TO 5 MILES SOUTH SOUTHEAST OF

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

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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...A SMALL/PERSISTENT MCS IS MOVING EWD ALONG THE I-10

CORRIDOR BETWEEN SAN ANTONIO AND HOUSTON.  BOUNDARY LAYER DEWPOINTS

NEAR 70 F AND SURFACE HEATING IN CLOUD BREAKS HAVE RESULTED IN

MODERATE INSTABILITY IN ADVANCE OF THE ONGOING STORMS...AND OTHER

CONVECTION IS INCREASING TO THE S AND E OF THIS MCS.  THOUGH

VERTICAL SHEAR AND INSTABILITY WEAKEN CONSIDERABLY TOWARD THE

HOUSTON AREA...THERE WILL BE A WINDOW OF OPPORTUNITY FOR THE STORMS

TO MAINTAIN A THREAT FOR AT LEAST ISOLATED LARGE HAIL AND DAMAGING

WINDS DURING THE AFTERNOON.



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 550. MEAN STORM

MOTION VECTOR 26020.





...THOMPSON

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