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000 

WWUS20 KWNS 291706

SEL9

SPC WW 291706

OKZ000-TXZ000-300100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 89

NWS STORM PREDICTION CENTER NORMAN OK

1210 PM CDT THU MAR 29 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTH CENTRAL OKLAHOMA

       NORTH CENTRAL TEXAS



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 1210 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 40

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

NORTHEAST OF ARDMORE OKLAHOMA TO 65 MILES SOUTH OF STEPHENVILLE

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...THUNDERSTORMS WILL CONTINUE IN A NNE-SSW ORIENTED BAND

ALONG AN OUTFLOW BOUNDARY ACROSS SRN OK INTO NRN AND CENTRAL TX.

SOME SURFACE HEATING SHOULD LEAD TO GRADUAL DESTABILIZATION E OF THE

ONGOING STORMS...WHICH WILL SUPPORT SOME INTENSIFICATION OF THE

CONVECTION THROUGH THE AFTERNOON.  THOUGH VERTICAL SHEAR PROFILES

ARE SUFFICIENT FOR ROTATING STORMS WITHIN THE BAND OF CONVECTION...A

TENDENCY FOR GRADUALLY WEAKENING LOW-LEVEL SHEAR THROUGH THE

AFTERNOON SUGGESTS THAT LARGE HAIL AND DAMAGING WINDS SHOULD BE THE

MAIN SEVERE THREATS.



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 500. MEAN STORM

MOTION VECTOR 22035.





...THOMPSON

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