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WWUS20 KWNS 291549

SEL5

SPC WW 291549

ILZ000-INZ000-LMZ000-292300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 435

NWS STORM PREDICTION CENTER NORMAN OK

1150 AM EDT FRI JUN 29 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHEASTERN ILLINOIS

       NORTHERN AND CENTRAL INDIANA

       LAKE MICHIGAN



EFFECTIVE THIS FRIDAY MORNING AND EVENING FROM 1150 AM UNTIL 700

PM EDT.



HAIL TO 2.5 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES NORTH OF

MARSEILLES ILLINOIS TO 35 MILES EAST NORTHEAST OF MUNCIE INDIANA.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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...CLUSTER OF TSTMS OVER NCNTRL IL HAS BECOME MORE N-S

ORIENTED WITH RESPECT TO THE DEEP LAYER MEAN FLOW AND WILL LIKELY

EVOLVE INTO SFC-BASED STORMS EARLY THIS AFTN IN SRN CHICAGO METRO

AREA.  STORMS WILL THEN PROPAGATE ESE INTO NRN/CNTRL IND THROUGH THE

AFTN WHERE MLCAPES WILL BE IN EXCESS OF 5000 J/KG.  VERY STEEP LAPSE

RATES AND AT LEAST 35-40 KTS OF MID-LVL FLOW WILL BE FAVORABLE FOR

VERY LARGE HAIL AND DMGG WIND GUSTS.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 29040.





...RACY

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