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000 

WWUS20 KWNS 180944

SEL1

SPC WW 180944

ILZ000-INZ000-KYZ000-181400-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 721

NWS STORM PREDICTION CENTER NORMAN OK

535 AM EDT THU OCT 18 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEASTERN ILLINOIS

       WESTERN AND CENTRAL INDIANA

       NORTHWESTERN KENTUCKY



EFFECTIVE THIS THURSDAY MORNING FROM 535 AM UNTIL 1000 AM EDT.



TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE

MILES EITHER SIDE OF A LINE FROM 65 MILES NORTH NORTHWEST OF

DANVILLE ILLINOIS TO 10 MILES SOUTH OF LOUISVILLE KENTUCKY.  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.



OTHER WATCH INFORMATION...CONTINUE...WW 718...WW 719...WW 720...



DISCUSSION...STRONG SHORTWAVE TROUGH IS MOVING NEWD THROUGH MO INTO

IL. THIS SYSTEM IS FORCING A LINE OF STORMS EAST-NORTHEASTWARD AT 50

KT THROUGH ILLINOIS INTO INDIANA.  STRONG ENVIRONMENTAL WINDS AND

THE FAST MOTION OF THE STORMS SUGGEST WIND DAMAGE IS THE MAIN

THREAT. HOWEVER...THE COMBINATION OF 1 KM SHEAR AT 40-50 KT AND

DEWPOINTS IN THE MID AND UPPER 60S INDICATE A POTENTIAL FOR ISOLATED

TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

450. MEAN STORM MOTION VECTOR 23050.





...IMY

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