

836 

WWUS20 KWNS 010054

SEL8

SPC WW 010054

OKZ000-010600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 218

NWS STORM PREDICTION CENTER NORMAN OK

755 PM CDT THU APR 30 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND NORTHWEST OKLAHOMA



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 755 PM

UNTIL 100 AM CDT.



HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 25 MILES SOUTH

SOUTHWEST OF GAGE OKLAHOMA TO 20 MILES SOUTHEAST OF CHANDLER

OKLAHOMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 217...



DISCUSSION...SCATTERED THUNDERSTORMS HAVE BEGUN TO FORM OVER

NORTHWEST OK ALONG A WEAK OUTFLOW BOUNDARY.  THESE STORMS MAY TRACK

SOUTHEASTWARD INTO CENTRAL OK THROUGH THE EVENING.  A VERY

MOIST/UNSTABLE AIRMASS AND SUFFICIENT EFFECTIVE SHEAR SUGGEST A RISK

OF SUPERCELLS CAPABLE OF VERY LARGE HAIL AND DAMAGING WINDS.



AVIATION...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 28025.





...HART

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