

811 

WWUS20 KWNS 192104

SEL4

SPC WW 192104

KSZ000-OKZ000-200400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 714

NWS STORM PREDICTION CENTER NORMAN OK

405 PM CDT WED AUG 19 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EXTREME SOUTHERN KANSAS

       NORTHERN AND CENTRAL OKLAHOMA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 405 PM UNTIL

1100 PM CDT.



TORNADOES...HAIL TO 2.5 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 70 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 50 MILES WEST SOUTHWEST OF

ALVA OKLAHOMA TO 60 MILES EAST SOUTHEAST OF PONCA CITY OKLAHOMA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 713...



DISCUSSION...A RESIDUAL OUTFLOW BOUNDARY IS BEGINNING TO LIFT SLOWLY

NWD ACROSS CENTRAL/NW OK AS THE LOW LEVELS MODIFY ON THE COOL SIDE

OF THE BOUNDARY.  DESTABILIZATION IS REDUCING CONVECTIVE INHIBITION

NEAR THE INTERSECTION OF THE OUTFLOW WITH A DIFFUSE TROUGH ACROSS

KS...AND THUNDERSTORM DEVELOPMENT MAY OCCUR IN THE NEXT 1-2 HOURS IN

THIS AREA FROM GAG-P28.  THE MESOSCALE ENVIRONMENT APPEARS FAVORABLE

FOR SUPERCELLS IN TERMS OF INSTABILITY AND DEEP LAYER VERTICAL

SHEAR...WHILE LOW-LEVEL SHEAR AND MOISTURE WILL BE SUFFICIENT FOR A

FEW TORNADOES WITH STORMS NEAR THE OUTFLOW BOUNDARY.  VERY LARGE

HAIL WILL ALSO BE POSSIBLE WITH ANY SUPERCELLS THAT FORM...AND THE

SEVERE THREAT WILL SPREAD EWD/ESEWD INTO THE OVERNIGHT HOURS.



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

SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE

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

550. MEAN STORM MOTION VECTOR 28025.





...THOMPSON

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