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930 

WWUS20 KWNS 181441

SEL9

SPC WW 181441

ALZ000-ARZ000-MOZ000-MSZ000-TNZ000-182200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 499

NWS STORM PREDICTION CENTER NORMAN OK

940 AM CDT SAT JUN 18 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF NORTHERN ALABAMA

       PARTS OF NORTHEASTERN ARKANSAS

       SMALL PART OF SOUTHEAST MISSOURI

       PARTS OF NORTHERN MISSISSIPPI

       MUCH OF WESTERN AND MIDDLE TENNESSEE



EFFECTIVE THIS SATURDAY MORNING AND AFTERNOON FROM 940 AM UNTIL

500 PM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

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 25 MILES SOUTH

SOUTHWEST OF JONESBORO ARKANSAS TO 65 MILES EAST NORTHEAST OF

HUNTSVILLE ALABAMA.  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.



DISCUSSION...ACTIVE MCS/S CONTINUED TO MOVE ESEWD INTO TN VALLEY.

AIR MASS WILL DESTABILIZE AHEAD OF CURRENT LINE OF STORMS WITH

MLCAPES AOA 2500 J/KG AND LITTLE CINH BY EARLY AFTERNOON.  WITH

STEEP MID LEVEL LAPSE RATES COUPLED WITH 30-40KT OF BRN SHEAR...THE

DAMAGING WIND THREAT WILL INCREASE RAPIDLY INTO THE AFTERNOON AS THE

SYSTEM ADVANCES ACROSS TN VALLEY.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 28030.





...HALES

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