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WWUS20 KWNS 241816

SEL1

SPC WW 241816

LAZ000-TXZ000-250000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 801

NWS STORM PREDICTION CENTER NORMAN OK

115 PM CDT WED AUG 24 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST LOUISIANA

       NORTHEAST TEXAS



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 115 PM UNTIL

700 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 40

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

SOUTHWEST OF LONGVIEW TEXAS TO 25 MILES NORTH NORTHEAST OF

ALEXANDRIA LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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...AN MCS IS MOVING SSWWD INTO A HOT/UNSTABLE AIR MASS

ACROSS NW LA/NE TX.  NEW THUNDERSTORM DEVELOPMENT IS BEING SUPPORTED

BY LIFT ALONG THE GUST FRONT...AND THERE IS SOME WEAK LARGE SCALE

SUPPORT FOR THUNDERSTORMS WITH A MIDLEVEL TROUGH MOVING SWD AROUND

THE ERN PERIPHERY OF THE SRN HIGH PLAINS UPPER RIDGE.  GIVEN

MODERATE INSTABILITY AND STEEPENING LOW-LEVEL LAPSE RATES...DAMAGING

GUSTS WILL BE POSSIBLE WITH THE STRONGER STORMS IN THE CLUSTER.



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 550. MEAN STORM

MOTION VECTOR 03035.





...THOMPSON

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