

890 

WWUS20 KWNS 112048

SEL1

SPC WW 112048

OKZ000-TXZ000-120300-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 151

NWS STORM PREDICTION CENTER NORMAN OK

350 PM CDT TUE MAY 11 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WESTERN OKLAHOMA

       WESTERN NORTH TEXAS



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 350 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 75 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 10 MILES SOUTHEAST OF

CHICKASHA OKLAHOMA TO 45 MILES WEST NORTHWEST OF ALTUS OKLAHOMA.

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.



DISCUSSION...ISOLATED SUPERCELL THUNDERSTORMS ARE EXPECTED TO

DEVELOP THIS AFTERNOON AND EVENING NEAR RETREATING DRYLINE...WHERE

STRONG HEATING HAS YIELDED EXTREME INSTABILITY.  INCREASING VERTICAL

WIND SHEAR THROUGH THE EVENING WILL ENHANCE THE RISK OF VERY LARGE

HAIL AND TORNADOES.



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

500. MEAN STORM MOTION VECTOR 24030.





...HART

