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106 

WWUS20 KWNS 031011

SEL1

SPC WW 031011

LAZ000-TXZ000-031600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 231

NWS STORM PREDICTION CENTER NORMAN OK

510 AM CDT SUN MAY 3 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND NORTHERN LOUISIANA

       EASTERN TEXAS



EFFECTIVE THIS SUNDAY MORNING FROM 510 AM UNTIL 1100 AM 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 105

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES SOUTHEAST OF

HUNTSVILLE TEXAS TO 30 MILES NORTH OF SHREVEPORT 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...SMALL LINE OF ELEVATED TSTMS OVER CENTRAL TX AT 10Z IS

MOVING EWD AT NEAR 50 KT AND SHOULD BEGIN INGESTING RICHER GULF

MOISTURE AS IT OVERSPREADS WARM SECTOR WITHIN THE HOUR OVER ERN TX.

AIR MASS REMAINS MODERATELY UNSTABLE WITHIN WARM SECTOR...WITH WEAK

CAPPING...AHEAD OF POTENT SHORTWAVE TROUGH EJECTING ACROSS TX.

STORMS MAY EVOLVE INTO A BOW ECHO AND RACE EWD INVOF STALLED SURFACE

OUTFLOW BOUNDARY/FRONT EXTENDING ACROSS ERN TX AND CENTRAL LA

THROUGH THE MORNING...WITH EVENTUAL BACKBUILDING ALONG COMPOSITE

OUTFLOW INTO SERN TX.  MARGINALLY SEVERE HAIL MAY ACCOMPANY ELEVATED

STORMS...ALTHOUGH WIND DAMAGE MAY BECOME PARAMOUNT AS STORMS ROOT

NEARER THE SURFACE THROUGH THE MORNING.



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 26040.





...EVANS

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