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WWUS20 KWNS 031720

SEL7

SPC WW 031720

LAZ000-TXZ000-032300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 337

NWS STORM PREDICTION CENTER NORMAN OK

1220 PM CDT SUN JUN 3 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND SOUTHWESTERN LOUISIANA

       EXTREME SOUTHEAST TEXAS



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1220 PM 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 60

STATUTE MILES EITHER SIDE OF A LINE FROM 75 MILES WEST NORTHWEST

OF FORT POLK LOUISIANA TO 75 MILES SOUTH SOUTHEAST OF ALEXANDRIA

LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 336...



DISCUSSION...A WELL-DEVELOPED MCS OVER E TX WILL CONTINUE MOVING

ESEWD AT ROUGHLY 40 KT INTO WRN LA THIS AFTERNOON.  SURFACE HEATING

HAS CONTRIBUTED TO MODERATE-STRONG INSTABILITY IN ADVANCE OF THE MCS

ACROSS SE TX AND WRN LA...AND A NARROW BELT OF 40-50 KT MID LEVEL

FLOW WILL ALSO HELP MAINTAIN THE ORGANIZED CONVECTIVE SYSTEM WITH

FAST COLD POOL MOTION.  DAMAGING WINDS WILL BE THE MAIN SEVERE

THREAT...THOUGH ISOLATED LARGE HAIL MAY ALSO OCCUR WITH THE MOST

INTENSE STORMS.



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 30040.





...THOMPSON

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