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144 

WWUS20 KWNS 082240

SEL7

SPC WW 082240

ILZ000-INZ000-090500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 747

NWS STORM PREDICTION CENTER NORMAN OK

540 PM CDT MON AUG 8 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND NORTHERN ILLINOIS

       NORTHWEST INDIANA



EFFECTIVE THIS MONDAY AFTERNOON FROM 540 PM UNTIL MIDNIGHT CDT.



HAIL TO 1.5 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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 15 MILES EAST

NORTHEAST OF MARSEILLES ILLINOIS TO 45 MILES SOUTH SOUTHWEST OF

BLOOMINGTON ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 746...



DISCUSSION...TSTM BAND IN NW IL HAS INTENSIFIED IN THE PAST HALF

HOUR AS SFC HEATING HAS SPREAD NEWD AHEAD OF IT IN WAKE OF LOOSELY

ORGANIZED CONVECTIVE SYSTEM NOW MOVING INTO IND.  SEASONABLY STRONG

SHORTWAVE IMPULSE AND ASSOCIATED WIND FIELD MOVING ESE INTO NRN

IL...COUPLED WITH HI PW VALUES AND NARROWING PLUME OF MID LVL LAPSE

RATES ON S SIDE OF SYSTEM...SUGGEST POTENTIAL FOR BOWING SEGMENTS

WITH DMGG WIND AND POSSIBLY MARGINALLY SVR HAIL.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 27025.





...CORFIDI

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