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WWUS20 KWNS 242022

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SPC WW 242022

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URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 97

NWS STORM PREDICTION CENTER NORMAN OK

320 PM CDT SAT APR 24 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       MUCH OF CENTRAL AND PARTS OF SOUTHERN ILLINOIS

       PARTS OF EASTERN MISSOURI



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 320 PM UNTIL

1000 PM CDT.



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

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 55 MILES SOUTH SOUTHWEST OF

QUINCY ILLINOIS TO 35 MILES EAST SOUTHEAST OF MATTOON ILLINOIS.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 94...WW 95...WW 96...



DISCUSSION...DEEPENING SURFACE LOW SW OF STL MOVING NNEWD TO NEAR

UIN THIS EVENING WITH VERY FAVORABLE SHEAR PROFILES FOR ROTATING

UPDRAFTS.  ALTHOUGH INSTABILITY IS MODEST...MORE THAN SUFFICIENT

GIVEN THE VERY STRONG KINEMATICS WITH DEEPENING SYSTEM  TO SUPPORT

BOTH QLCS LINEAR MODE AND POSSIBLE DISCRETE STORMS.  IN ADDITION TO

WIND DAMAGE TORNADO'S ARE POSSIBLE WITH EITHER MODE AS ACTIVITY

MOVES/DEVELOP N/E ACROSS THE WATCH AREA.



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

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 21035.





...HALES

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