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WWUS20 KWNS 010549

SEL9

SPC WW 010549

ARZ000-KSZ000-MOZ000-OKZ000-011200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 219

NWS STORM PREDICTION CENTER NORMAN OK

1245 AM CDT FRI MAY 1 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHWESTERN ARKANSAS

       FAR SOUTHEASTERN KANSAS

       SOUTHWESTERN MISSOURI

       CENTRAL AND NORTHEASTERN OKLAHOMA



EFFECTIVE THIS FRIDAY MORNING FROM 1245 AM UNTIL 700 AM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 60

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES NORTHEAST

OF FAYETTEVILLE ARKANSAS TO 30 MILES NORTH NORTHWEST OF OKLAHOMA

CITY OKLAHOMA.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 218...



DISCUSSION...SUPERCELLS IN CENTRAL OK ARE EXPECTED TO CONTINUE THE

COUPLE OF HOURS AND THEN GRADUALLY WEAKEN. HOWEVER...OTHER STORMS

ARE EXPECTED TO REDEVELOP ACROSS THE WATCH AREA THROUGH THE EARLY

MORNING HOURS AS LOW LEVEL JET STRENGTHENS/VEERS AND IMPINGES ON

WEAK BOUNDARY...STRETCHING SEWD FROM NORTH CENTRAL INTO EAST CENTRAL

OK. MUCAPES AOA 2000 J/KG AND EFFECTIVE SHEAR AT 40-50 KT WILL BE

SUPPORTIVE OF ROTATING STORMS. HOWEVER...A SLOWLY STABILIZING

BOUNDARY LAYER SUGGESTS LARGE HAIL SHOULD BE THE PRIMARY THREAT.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 50

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 29025.





...IMY

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