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WWUS20 KWNS 022039

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ILZ000-MOZ000-030200-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 420

NWS STORM PREDICTION CENTER NORMAN OK

340 PM CDT THU JUN 2 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WEST CENTRAL ILLINOIS

       EAST CENTRAL MISSOURI



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 340 PM UNTIL

900 PM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 40 STATUTE

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

COLUMBIA MISSOURI TO 10 MILES EAST NORTHEAST OF SAINT LOUIS

MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 419...



DISCUSSION...A SMALL CLUSTER OF SEVERE/SUPERCELL THUNDERSTORMS HAVE

FORMED OVER CENTRAL MO...NEAR A REMNANT MCV.  THESE STORMS ARE

EXPECTED TO TRACK EASTWARD INTO THE WATCH AREA THIS

AFTERNOON...WHILE OTHER STORMS POTENTIALLY FORM ALONG OLD OUTFLOW

BOUNDARY EXTENDING FROM MCV TO SOUTH OF STL.  STRONG DEEP LAYER

EFFECTIVE SHEAR AND AMPLE CAPE WILL POSE A RISK OF SUPERCELLS

CAPABLE OF LARGE HAIL AND DAMAGING WINDS.  BACKED LOW LEVEL WINDS

NORTH OF THE OUTFLOW BOUNDARY COULD ALSO POSE A THREAT OF AN

ISOLATED TORNADO.



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

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 29025.





...HART

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