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709 

WWUS20 KWNS 221830

SEL8

SPC WW 221830

ILZ000-INZ000-KYZ000-222300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 178

NWS STORM PREDICTION CENTER NORMAN OK

135 PM CDT FRI APR 22 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN ILLINOIS

       SOUTHERN INDIANA

       NORTH CENTRAL KENTUCKY



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 135 PM UNTIL 600

PM CDT.



HAIL TO 2 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 45

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTHWEST

OF MOUNT VERNON ILLINOIS TO 65 MILES NORTHEAST OF LOUISVILLE

KENTUCKY.  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.



DISCUSSION...A PERSISTENT CLUSTER OF THUNDERSTORMS OVER CENTRAL IL

IS LIKELY TO INTENSIFY THROUGH THE AFTERNOON AS IT TRACKS ACROSS THE

WATCH AREA.  AIRMASS DESTABILIZATION COUPLED WITH CONVERGENCE ALONG

THE WARM FRONT WILL HELP TO SUPPORT THE POTENTIAL FOR DAMAGING WINDS

AND LARGE HAIL IN THE STRONGER STORMS.



AVIATION...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 27035.





...HART

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