

246 

WWUS20 KWNS 140239

SEL8

SPC WW 140239

ARZ000-OKZ000-TXZ000-140900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 298

NWS STORM PREDICTION CENTER NORMAN OK

940 PM CDT WED MAY 13 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST ARKANSAS

       SOUTHERN AND EASTERN OKLAHOMA

       A SMALL PART OF NORTHWEST TEXAS



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 940 PM

UNTIL 400 AM 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 105

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTHWEST OF

HARRISON ARKANSAS TO 35 MILES WEST SOUTHWEST OF ARDMORE OKLAHOMA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 293...WW 295...WW

296...WW 297...



DISCUSSION...A BROKEN BAND OF SEVERE STORMS...WITH SOME EMBEDDED

SUPERCELLS...CONTINUES TO DEVELOP SWD/SEWD ALONG THE COLD FRONT

ACROSS OK.  DESPITE THE LOSS OF DAYTIME HEATING...STRONG INSTABILITY

AND PRONOUNCED CONVERGENCE/LOW-LEVEL FRONTOGENESIS WILL HELP

MAINTAIN EXISTING STORMS AND SUPPORT NEW DEVELOPMENT FOR THE NEXT

SEVERAL HOURS.  LARGE HAIL CAN BE EXPECTED WITH THE STRONGEST

STORMS...WHILE THE DAMAGING WIND THREAT SHOULD INCREASE SOME AS A

RESULT OF STORM MERGERS/INTERACTIONS AND SUBSEQUENT COLD POOL AND

SMALL BOW ECHO FORMATION.



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 550. MEAN STORM

MOTION VECTOR 32020.





...THOMPSON

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