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028 

WWUS20 KWNS 122242

SEL0

SPC WW 122242

TXZ000-130400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 290

NWS STORM PREDICTION CENTER NORMAN OK

540 PM CDT TUE MAY 12 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       THE SOUTHEAST TEXAS PANHANDLE INTO WEST CENTRAL TEXAS



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 540 PM UNTIL

1100 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 EAST AND WEST OF A LINE FROM 60 MILES NORTH

NORTHWEST OF CHILDRESS TEXAS TO 40 MILES SOUTHWEST OF SAN ANGELO

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

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 289...



DISCUSSION...HIGH-BASED CONVECTION IN THE DEEPLY MIXED ENVIRONMENT

ALONG AND W OF THE DRYLINE MAY SPREAD E FAR ENOUGH TO REACH SOMEWHAT

RICHER MOISTURE AND STRONGER INSTABILITY NEAR THE CAPROCK THIS

EVENING.  VERY STEEP MID LEVEL LAPSE RATES AND MODEST DEEP LAYER

VERTICAL SHEAR IN ADVANCE OF A WEAK MID LEVEL WAVE EJECTING NEWD

FROM SE NM COULD SUPPORT A FEW SUPERCELLS WITH LARGE HAIL/DAMAGING

WINDS...AND CONVECTION MAY EVOLVE INTO ONE OR TWO SMALL CLUSTERS

EARLY TONIGHT.  THE EWD EXTENT OF THE SEVERE THREAT WILL BE LIMITED

BY STRONG CONVECTIVE INHIBITION AFTER SUNSET.



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 500. MEAN STORM

MOTION VECTOR 27020.





...THOMPSON

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