

000 

WWUS20 KWNS 200942

SEL7

SPC WW 200942

OKZ000-TXZ000-201700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 427

NWS STORM PREDICTION CENTER NORMAN OK

440 AM CDT WED JUN 20 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       A SMALL PART OF SOUTHERN OKLAHOMA

       CENTRAL AND EASTERN TEXAS



EFFECTIVE THIS WEDNESDAY MORNING FROM 440 AM UNTIL NOON CDT.



HAIL TO 1 INCH 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 85

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES EAST

NORTHEAST OF TYLER TEXAS TO 75 MILES WEST NORTHWEST OF AUSTIN

TEXAS.  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 425...WW 426...



DISCUSSION...CNTRL/N CNTRL TX SQLN EXPECTED TO CONTINUE S/SE AT 30+

KTS.  GUST FRONT WILL ENCOUNTER INCREASING CIN WITH SEWD EXTENT AND

DEEP SHEAR WILL REMAIN MINIMAL.  BUT MOMENTUM OF ASSOCIATED 40-50 KT

2 KM DEEP REAR INFLOW JET /PER DYS AND FDR VWP DATA/ AND RICH

MOISTURE SUPPLY/MODERATE SSE LLJ AHEAD OF BOUNDARY SUGGEST POTENTIAL

ISOLATED DAMAGING WET MICROBURSTS.  TSTM COVERAGE/STRENGTH MAY ALSO

INCREASE LATER THIS MORNING IN THE AREA BETWEEN ACT...AUS...AND CLL

AS GUST FRONT ENCOUNTERS WEAKER WNW-MOVING BOUNDARY THAT RECENTLY

PASSED THE HOU AREA.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM MOTION

VECTOR 33030.





...CORFIDI

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