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042 

WWUS20 KWNS 212130

SEL3

SPC WW 212130

TXZ000-220400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 743

NWS STORM PREDICTION CENTER NORMAN OK

430 PM CDT MON SEP 21 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTH CENTRAL TEXAS



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 430 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 90

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH OF

DALLAS TEXAS TO 30 MILES SOUTHWEST OF STEPHENVILLE TEXAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU3).



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 742...



DISCUSSION...THUNDERSTORMS ARE DEVELOPING ALONG THE DRYLINE FROM

JUST E OF SPS TO E OF ABI.  STRONG INSTABILITY AND EFFECTIVE BULK

SHEAR AROUND 30 KT WILL SUPPORT A FEW PERSISTENT MULTICELL

CLUSTERS...AS WELL AS STORMS WITH SOME SUPERCELL STRUCTURES.  LARGE

HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS.  LATER THIS

EVENING...STORM INTERACTIONS COULD LEAD TO UPSCALE GROWTH INTO MORE

OF A LINEAR MCS...WITH A CONTINUING THREAT FOR DAMAGING WINDS AND

LARGE HAIL.



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 27025.





...THOMPSON

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