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000 

WWUS20 KWNS 071553

SEL2

SPC WW 071553

OKZ000-TXZ000-072300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 252

NWS STORM PREDICTION CENTER NORMAN OK

1050 AM CDT MON MAY 7 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTH CENTRAL AND SOUTHEAST OKLAHOMA

       NORTH CENTRAL TEXAS



EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1050 AM UNTIL 600

PM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 70 MILES WEST SOUTHWEST OF

ARDMORE OKLAHOMA TO 50 MILES NORTH NORTHEAST OF PARIS TEXAS.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



DISCUSSION...ONGOING STRONG TO SEVERE THUNDERSTORMS EXPECTED TO

CONTINUE INCREASING IN COVERAGE AND INTENSITY ALONG NOSE OF

WEAKENING LLJ TODAY.  SURFACE HEATING WILL BOOST MLCAPE AND WEAKEN

CAP DURING THE NEXT FEW HOURS...WITH MLCAPE FROM 1500-2500 J/KG

EXPECTED BY THE EARLY AFTERNOON ALONG THE RED RIVER VALLEY.  DEEP

LAYER SHEAR WILL REMAIN MARGINAL FOR SUSTAINED SUPERCELLS.

HOWEVER...STRONG LOW LEVEL SHEAR AND FAVORABLE LOW LEVEL

THERMODYNAMICS WILL SUPPORT AT LEAST A RISK OF BRIEF-LIVED

TORNADOES.  LARGE HAIL AND DAMAGING WINDS WILL ALSO BECOME COMMON

WITH THE STRONGER STORMS.



AVIATION...TORNADOES AND 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 22025.





...EVANS

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