

000 

WWUS20 KWNS 071231

SEL2

SPC WW 071231

ARZ000-MOZ000-OKZ000-071800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 272

NWS STORM PREDICTION CENTER NORMAN OK

735 AM CDT WED MAY 7 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST ARKANSAS

       SOUTHWEST AND SOUTH CENTRAL MISSOURI

       EAST CENTRAL AND NORTHEAST OKLAHOMA



EFFECTIVE THIS WEDNESDAY MORNING AND AFTERNOON FROM 735 AM UNTIL

100 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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTH

NORTHEAST OF SPRINGFIELD MISSOURI TO 20 MILES SOUTHEAST OF

MCALESTER OKLAHOMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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.



DISCUSSION...ELEVATED CONVECTION WILL LIKELY PERSIST THROUGH THE

MORNING ALONG THE INSTABILITY GRADIENT FROM ERN OK NEWD INTO SW MO.

THE 12Z SPRINGFIELD SOUNDING REVEALED MUCAPE OF ABOUT 2300 J/KG

BASED NEAR 850 MB AND MID LEVEL LAPSE RATES OF 7.5 C/KM...WHICH

SHOULD SUPPORT A CONTINUED THREAT FOR LARGE HAIL THROUGH AT LEAST

LATE MORNING.



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 24035.





...THOMPSON

