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WWUS20 KWNS 021947

SEL4

SPC WW 021947

ILZ000-INZ000-MOZ000-LMZ000-030300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 584

NWS STORM PREDICTION CENTER NORMAN OK

245 PM CDT SAT JUL 2 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL ILLINOIS

       EXTREME NORTHWEST INDIANA

       EAST-CENTRAL MISSOURI

       LAKE MICHIGAN



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

1000 PM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

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

VALPARAISO INDIANA TO COLUMBIA MISSOURI.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU4).



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 583...



DISCUSSION...BANDS OF PRIMARILY MULTICELL TSTMS WILL INITIATE ALONG

A SEGMENTED COLD FRONT SITUATED FROM SRN LAKE MI TO ECNTRL MO.

THOUGH VERTICAL SHEAR PROFILES ARE ANEMIC...VERY STEEP LAPSE RATES

FROM SFC TO 500 MB WILL ENCOURAGE VIGOROUS UPDRAFTS.  DAMAGING WIND

GUSTS APPEAR TO BE THE PRIMARY THREAT...BUT BRIEF STRONGER UPDRAFTS

MAY YIELD LARGE HAIL AS WELL.  STORM MOTION WILL NOT BE PARTICULARLY

FAST OWING TO WEAK TROPOSPHERIC WINDS.  ACTIVITY WILL GRADUALLY

REACH FAR NWRN IND AND CNTRL IL BY THIS EVENING.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

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

MOTION VECTOR 26025.





...RACY

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