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219 

WWUS20 KWNS 210258

SEL5

SPC WW 210258

ARZ000-LAZ000-OKZ000-TXZ000-210900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 725

NWS STORM PREDICTION CENTER NORMAN OK

1000 PM CDT THU AUG 20 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN ARKANSAS

       NORTHERN LOUISIANA

       SOUTHERN OKLAHOMA

       NORTH CENTRAL AND NORTHEAST TEXAS



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1000 PM

UNTIL 400 AM 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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF

SHERMAN TEXAS TO 10 MILES SOUTHEAST OF EL DORADO ARKANSAS.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU5).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 722. WATCH NUMBER 722 WILL NOT

BE IN EFFECT AFTER 1000 PM CDT. CONTINUE...WW 723...WW 724...



DISCUSSION...TSTMS EXPECTED TO CONTINUE FORMING INVOF THE RED RVR

AND OVER THE ARKLATEX AS POCKET OF STRONG INSTABILITY IS

INCREASINGLY UNDERCUT BY STRENGTHENING COLD FRONT.  ALTHOUGH LOW LVL

INFLOW WILL BE WEAK...INCREASING UPLIFT ABOVE FRONTAL

SURFACE...GLANCING INFLUENCE OF MO UPR VORT...AND MOIST LOW LVL

ENVIRONMENT SUGGEST POTENTIAL FOR ISOLD DMGG WIND AND HAIL THROUGH

EARLY FRIDAY.



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 30020.





...CORFIDI

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