WATCHES: Tornado Watch Number 356

WWUS20 KWNS 241755
SEL6
SPC WW 241755
OKZ000-TXZ000-250300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 356
NWS STORM PREDICTION CENTER NORMAN OK
1250 PM CDT TUE MAY 24 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

WESTERN AND CENTRAL OKLAHOMA
NORTHWEST AND NORTH-CENTRAL TEXAS

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1250 PM UNTIL
1000 PM CDT.

...THIS IS A PARTICULARLY DANGEROUS SITUATION...

DESTRUCTIVE TORNADOES...LARGE HAIL TO 3 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 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES WEST NORTHWEST OF
PONCA CITY OKLAHOMA TO 25 MILES SOUTH SOUTHWEST OF FORT WORTH
TEXAS. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

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 352...WW 354...WW 355...

DISCUSSION...TSTM INITIATION IS ANTICIPATED WITHIN THE NEXT HOUR OR
TWO ALONG THE DRYLINE FROM WRN OK INTO W-CNTRL TX. STRONG HEIGHT
FALLS/DYNAMIC FORCING FOR ASCENT ASSOCIATED WITH NEGATIVELY TILTED
MIDLEVEL TROUGH EMERGING INTO THE PLAINS SHOULD SUPPORT A RAPID
INCREASE IN STORM COVERAGE THROUGH THE AFTERNOON. WARM SECTOR AIR
MASS IS CHARACTERIZED BY A VERY MOIST BOUNDARY LAYER WITH DEWPOINTS
IN THE UPPER 60S TO LOWER 70S. WHEN COUPLED WITH STEEP MIDLEVEL
LAPSE RATES...ENVIRONMENT IS MODERATELY TO STRONGLY UNSTABLE WITH
MLCAPE VALUES OF 2500-4000 J/KG. DEEP-LAYER SHEAR STRENGTHENING TO
40-50 KT WILL PROMOTE RAPID SUPERCELL DEVELOPMENT WITH THE INITIAL
HAZARD BEING VERY LARGE HAIL. INITIAL VEER-BACK WIND PROFILE
OBSERVED IN CURRENT VADS/PROFILERS IS EXPECTED TO TRANSITION TO
LARGE CLOCKWISE CURVED HODOGRAPHS BY 00Z WHERE 0-1 KM SRH WILL
APPROACH 400-500 M2/S2. AS SUCH...EXPECT A RAPID INCREASE IN THE
THREAT FOR TORNADOES THIS AFTERNOON INTO EVENING...SOME OF WHICH
COULD BE LONG-TRACKED AND STRONG TO VIOLENT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
550. MEAN STORM MOTION VECTOR 23035.

...MEAD

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