

000 

WWUS20 KWNS 130623

SEL9

SPC WW 130623

LAZ000-TXZ000-CWZ000-131500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 669

NWS STORM PREDICTION CENTER NORMAN OK

120 AM CDT THU SEP 13 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHERN LOUISIANA

       EXTREME SOUTHEAST TEXAS

       COASTAL WATERS



EFFECTIVE THIS THURSDAY MORNING FROM 120 AM UNTIL 1000 AM CDT.



TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 30 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 15 MILES WEST OF PORT ARTHUR

TEXAS TO 25 MILES SOUTHEAST OF LAFAYETTE LOUISIANA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU9).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



DISCUSSION...POTENTIAL FOR ISOLATED TORNADOES WILL INCREASE THROUGH

ABOUT SUNRISE ALONG THE NWRN GULF CST FROM EXTREME SE TX INTO S

CNTRL LA AS CIRCULATION OF HRCN HUMBERTO MOVES INLAND.  GREATEST

THREAT SHOULD EXIST AT INTERSECTION OF OUTER CONFLUENCE BAND WITH

SLOW NWD-MOVING W-E FRONT NOW ALONG THE IMMEDIATE LA CST.  SRH FOR

CELLS MOVING NWD AT 20 KTS HAS INCREASED TO AOA 175 M2/S2 IN THE

PAST 2 HRS USING THE LCH VWP.  VALUES SHOULD INCREASE TO AOA 250

M2/S2 BY 09-12Z ALONG THE CNTRL AND SW LA GULF CST...AS SFC

DEWPOINTS RISE INTO MID 70S.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

450. MEAN STORM MOTION VECTOR 17035.





...CORFIDI

