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WWUS20 KWNS 272050

SEL1

SPC WW 272050

KSZ000-OKZ000-280300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 21

NWS STORM PREDICTION CENTER NORMAN OK

250 PM CST SUN FEB 27 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       SMALL PART OF SOUTH CENTRAL AND SOUTHEAST KANSAS

       NORTH CENTRAL OKLAHOMA



EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 250 PM UNTIL 900

PM CST.



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 40 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH SOUTHWEST OF

ALVA OKLAHOMA TO 25 MILES EAST SOUTHEAST OF CHANUTE KANSAS.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU1).



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 20...



DISCUSSION...VISIBLE IMAGERY SHOWS DEEPENING CUMULUS NEAR AND E OF

THE TRIPLE POINT ACROSS N CENTRAL OK.  A SEPARATE BAND OF HIGH-BASED

CUMULUS IN NW OK DEMARCATES THE STRONG DRY SURGE AND SUGGESTS AN

INCREASE IN LOW-LEVEL CONVERGENCE/ASCENT NEAR THE TRIPLE POINT IN

THE NEXT COUPLE OF HOURS.  NOW THAT SURFACE TEMPERATURES HAVE WARMED

INTO THE 70S...THE CAP IS WEAKENING AND THUNDERSTORM DEVELOPMENT

APPEARS PROBABLE BY 22-23Z.  STRONG DEEP-LAYER SHEAR AND MLCAPE

APPROACHING 1500 J/KG WILL SUPPORT SUPERCELLS CAPABLE OF PRODUCING

LARGE HAIL. A COUPLE OF TORNADOES WILL BE POSSIBLE GIVEN 0-1 KM SRH

AOA 200 M2/S2 AND THE POTENTIAL FOR STORMS TO MOVE NEAR/ALONG THE

SURFACE WARM FRONT THIS EVENING.



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 25040.





...THOMPSON

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