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310 

WWUS20 KWNS 271802

SEL8

SPC WW 271802

ARZ000-OKZ000-TXZ000-280100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 78

NWS STORM PREDICTION CENTER NORMAN OK

100 PM CDT FRI MAR 27 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHWEST ARKANSAS

       EXTREME SOUTHEAST OKLAHOMA

       NORTHEAST TEXAS



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 100 PM UNTIL 800

PM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

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

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH OF PARIS TEXAS

TO 20 MILES WEST SOUTHWEST OF LUFKIN TEXAS.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU8).



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.



OTHER WATCH INFORMATION...CONTINUE...WW 76...WW 77...



DISCUSSION...THUNDERSTORMS ARE DEVELOPING IN A BROKEN BAND E OF THE

SURFACE COLD FRONT AND IN ASSOCIATION WITH A BELT OF ASCENT

ALOFT...GENERALLY E OF I-45.  CLOUDS...A THUNDERSTORM CLUSTER

FARTHER S IN SE TX...AND WEAK LOW-LEVEL FLOW HAVE ALL MUDDLED THE

ENVIRONMENT ACROSS NE TX...WITH PROFILES NOT PARTICULARLY FAVORABLE

FOR SUPERCELLS AT THE MOMENT.  HOWEVER...AS THE MID LEVEL AND

SURFACE CYCLONES MOVE EWD ACROSS N TX...LOW-LEVEL SHEAR SHOULD

GRADUALLY INCREASE OVER NE TX AND THE LOW LEVELS SHOULD DESTABILIZE

WITHIN SOME CLOUD BREAKS.  BY LATER THIS AFTERNOON...THERE WILL BE

AN INCREASE IN THE THREAT FOR SUPERCELLS WITH A COUPLE OF

TORNADOES...IN ADDITION TO THE LARGE HAIL/DAMAGING WIND THREAT.



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

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

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

450. MEAN STORM MOTION VECTOR 23030.





...THOMPSON

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