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647 

WWUS20 KWNS 241854

SEL9

SPC WW 241854

ILZ000-INZ000-MIZ000-OHZ000-250200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 529

NWS STORM PREDICTION CENTER NORMAN OK

155 PM CDT SAT JUL 24 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       A LARGE PART OF NORTHERN AND CENTRAL ILLINOIS

       MUCH OF NORTHERN INDIANA

       PARTS OF SOUTHERN LOWER MICHIGAN

       PARTS OF NORTHWEST OHIO



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

900 PM CDT.



HAIL TO 1 INCH 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 65 MILES SOUTH

SOUTHWEST OF MOLINE ILLINOIS TO 65 MILES EAST NORTHEAST OF FORT

WAYNE INDIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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...THUNDERSTORMS EXPECTED TO INCREASE IN NUMBER AND

INTENSITY FROM WEST TO EAST ACROSS THE WATCH AREA. GIVEN MLCAPES AOA

3000 J/KG AND 30-35 KT OF SHEAR...WIND DAMAGE WILL BECOME THE

PRIMARY THREAT AS STORMS DEVELOP COLD POOLS AND EVOLVE INTO LINE

SEGMENTS AND SHORT BOWS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.

A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM MOTION

VECTOR 26030.





...HALES

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