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166 

WWUS20 KWNS 261708

SEL5

SPC WW 261708

ALZ000-ARZ000-MSZ000-TNZ000-270100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 555

NWS STORM PREDICTION CENTER NORMAN OK

1210 PM CDT SUN JUN 26 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN ALABAMA

       FAR NORTHEAST ARKANSAS

       NORTHERN MISSISSIPPI

       SOUTHWEST AND SOUTHERN-MIDDLE TENNESSEE



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1210 PM UNTIL

800 PM 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES WEST

SOUTHWEST OF MEMPHIS TENNESSEE TO 45 MILES NORTHEAST OF GADSDEN

ALABAMA.  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.



DISCUSSION...LINEAR MCS OVER PORTIONS OF WRN AND MIDDLE TN IS

EXPECTED TO CONTINUE SWD INTO TO A HOT...MOIST AND MODERATELY TO

STRONGLY UNSTABLE ENVIRONMENT WITH MLCAPE OF 2500-3500 J/KG.

ADDITIONAL STORM DEVELOPMENT WILL BE POSSIBLE ALONG OUTFLOW BOUNDARY

PRECEDING MCS OVER NRN AL.  THOUGH VERTICAL SHEAR WILL REMAIN

MARGINALLY STRONG FOR STORM ORGANIZATION...THE DEGREE OF INSTABILITY

AND COLD POOL ORGANIZATION OF ONGOING STORMS SUGGEST THE POTENTIAL

FOR DAMAGING WINDS AND HAIL THIS AFTERNOON AND EVENING.



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 32025.





...MEAD

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