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548 

WWUS20 KWNS 231934

SEL5

SPC WW 231934

OKZ000-TXZ000-240300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 345

NWS STORM PREDICTION CENTER NORMAN OK

230 PM CDT MON MAY 23 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN OKLAHOMA

       NORTHWEST TEXAS



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 230 PM UNTIL

1000 PM CDT.



TORNADOES...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 60 STATUTE

MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF ALVA

OKLAHOMA TO 40 MILES SOUTH SOUTHEAST OF ALTUS OKLAHOMA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU5).



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 338...WW 339...WW

340...WW 341...WW 342...WW 343...WW 344...



DISCUSSION...TCU/INCIPIENT TSTM DEVELOPMENT IS IN PROGRESS ALONG

DRYLINE IN WRN OK SW OF CSM.  MODIFICATION OF 19Z OUN SOUNDING FOR

AIR MASS IMMEDIATELY E OF DRYLINE SUGGESTS THAT ENVIRONMENT IS

NEARLY UNCAPPED WITH MLCAPE OF 4000-5000 J/KG.  WHILE PASSAGE OF

SHORT WAVE TROUGH TO THE NE IS NOT PARTICULARLY WELL-TIMED...STRONG

DIABATIC HEATING W OF DRYLINE SHOULD SERVE TO FOSTER AT LEAST

ISOLATED STORM DEVELOPMENT THIS AFTERNOON INTO EVENING.

INITIALLY...VERY LARGE HAIL WILL BE THE PRIMARY HAZARD WITH MATURE

SUPERCELLS GIVEN THE LOCALLY HIGHER T-TD SPREADS AND WEAK LOW-LEVEL

FLOW.  THE POTENTIAL FOR TORNADOES WILL INCREASE THIS EVENING AS

LOW-LEVEL SHEAR STRENGTHENS AND LCL HEIGHTS LOWER.



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

600. MEAN STORM MOTION VECTOR 27020.





...MEAD

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