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WWUS20 KWNS 281528

SEL0

SPC WW 281528

ALZ000-ARZ000-LAZ000-MSZ000-282300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 570

NWS STORM PREDICTION CENTER NORMAN OK

1025 AM CDT TUE JUN 28 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN ALABAMA

       FAR SOUTHEAST ARKANSAS

       NORTHEAST LOUISIANA

       CENTRAL AND SOUTHERN MISSISSIPPI



EFFECTIVE THIS TUESDAY MORNING AND EVENING FROM 1025 AM UNTIL 600

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 85

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 70 MILES NORTH

NORTHWEST OF NATCHEZ MISSISSIPPI TO 20 MILES EAST NORTHEAST OF

MONTGOMERY ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 568...WW 569...



DISCUSSION...CONVECTIVE OUTFLOW ASSOCIATED WITH NOCTURNAL MCS

ACTIVITY WILL SERVE TO FOCUS RENEWED TSTM DEVELOPMENT TODAY.  INFLOW

AIR MASS ACROSS THE WATCH AREA IS CHARACTERIZED BY HIGH MOISTURE

CONTENT /I.E. PW VALUES ABOVE 1.75 INCHES/ AND STEEP MIDLEVEL LAPSE

RATES WHICH WILL RESULT IN MLCAPE OF 2000-3500 J/KG.  VERTICAL SHEAR

WILL REMAIN RELATIVELY WEAK...BUT THE DEGREE OF INSTABILITY AND

POTENTIAL FOR STRONG COLD POOL DEVELOPMENT WILL BE FAVORABLE FOR

DAMAGING WINDS AND SOME HAIL.



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 32030.





...MEAD

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