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WWUS20 KWNS 040459

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 723

NWS STORM PREDICTION CENTER NORMAN OK

1200 AM CDT THU AUG 4 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN AND CENTRAL ALABAMA



EFFECTIVE THIS THURSDAY MORNING FROM MIDNIGHT UNTIL 500 AM CDT.



HAIL TO 1 INCH 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 OF

HUNTSVILLE ALABAMA TO 45 MILES SOUTH SOUTHEAST OF BIRMINGHAM

ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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...STORMS ARE COALESCING ALONG THE LEADING EDGE OF THE

COMPOSITE COLD POOL GENERATED BY STORM MERGING OVER SRN MIDDLE

TN...WITH ACTIVITY EXPECTED TO PROPAGATE SSEWD INTO NRN AL EARLY

THIS MORNING.  00Z BMX RAOB SHOWED EXTENSIVE DCAPE AND SUBSTANTIAL

PWAT TO ENHANCE THREAT FOR DAMAGING WIND GUSTS...WITHIN DRY

MID/UPPER LEVEL AIR MASS AS INDICATED BY WATER VAPOR IMAGERY.  THERE

IS POTENTIAL FOR BACKBUILDING OF NEW STORMS ALONG THE WRN FLANK OF

THE LINE OF STORMS...WHICH MAY ENHANCE SWD PROPAGATION OF THE

SYSTEM.



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

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

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

VECTOR 32025.





...WEISS

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