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WWUS20 KWNS 291733

SEL8

SPC WW 291733

TXZ000-300100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 198

NWS STORM PREDICTION CENTER NORMAN OK

1235 PM CDT SUN APR 29 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SOUTHWEST TEXAS



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1235 PM UNTIL

800 PM CDT.



TORNADOES...HAIL TO 1.5 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 60 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 55 MILES NORTH NORTHWEST OF

MARFA TEXAS TO 40 MILES NORTH NORTHEAST OF DEL RIO 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.



DISCUSSION...MID LEVEL LOW OVER NRN MEXICO WILL EJECT SLOWLY ENEWD

TOWARD THE BIG BEND THROUGH THE AFTERNOON.  INCREASING MID LEVEL

SWLY FLOW WILL OVERSPREAD THE BIG BEND AND LOWER PECOS VALLEY ABOVE

LOW-LEVEL ESELY FLOW...WHILE THE MID LEVEL DRY SLOT WILL ALLOW

POCKETS OF STRONGER SURFACE HEATING/DESTABILIZATION.  EXPECT

ADDITIONAL STORMS TO FORM THIS AFTERNOON OVER THE HIGHER TERRAIN AND

SPREAD NWD/NEWD...WITH THE POTENTIAL FOR SUPERCELLS WITH LARGE HAIL

AND ISOLATED DAMAGING WINDS.  ADDITIONALLY...SUBSTANTIAL MOISTURE

AND BUOYANCY IN THE LOW LEVELS...ALONG WITH THE SUPERCELL WIND

PROFILE...COULD SUPPORT A COUPLE OF TORNADOES.



AVIATION...TORNADOES AND 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 22020.





...THOMPSON

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