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922 

WWUS20 KWNS 151209

SEL9

SPC WW 151209

ARZ000-LAZ000-MSZ000-151800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 769

NWS STORM PREDICTION CENTER NORMAN OK

710 AM CDT THU OCT 15 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME SOUTHERN ARKANSAS

       NORTH AND NORTHEAST LOUISIANA

       WEST CENTRAL MISSISSIPPI



EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 710 AM UNTIL

100 PM 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 70

STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES NORTHWEST OF

MONROE LOUISIANA TO 35 MILES WEST SOUTHWEST OF NATCHEZ

MISSISSIPPI.  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...A CLUSTER OF THUNDERSTORMS OVER SRN AR WILL LIKELY

PERSIST AND MOVE SEWD ACROSS N/NE LA AND W CENTRAL MS THROUGH ABOUT

MIDDAY.  THE CONVECTION WILL BE SUPPORTED BY AN INFLUX OF LOW-MID

70S BOUNDARY LAYER DEWPOINTS...MLCAPE VALUES NEAR 2000 J/KG...AND

INCREASINGLY UNIDIRECTIONAL DEEP LAYER SHEAR PROFILES IN ADVANCE OF

A WEAK WAVE ON THE SURFACE FRONT IN EXTREME NE TX.  DAMAGING WINDS

SHOULD BE THE PRIMARY SEVERE STORM THREAT THROUGH THE MORNING.



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 31025.





...THOMPSON

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