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601 

WWUS20 KWNS 261927

SEL4

SPC WW 261927

ILZ000-INZ000-KYZ000-MOZ000-270200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 744

NWS STORM PREDICTION CENTER NORMAN OK

230 PM CDT SAT SEP 26 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF SOUTHERN ILLINOIS

       SMALL PART OF SOUTHWEST INDIANA

       MUCH OF WESTERN KENTUCKY

       PARTS OF SOUTHEAST MISSOURI



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 230 PM UNTIL

900 PM CDT.



HAIL TO 2 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 75

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST

NORTHEAST OF SALEM ILLINOIS TO 35 MILES SOUTH SOUTHEAST OF

PADUCAH KENTUCKY.  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.



DISCUSSION...THUNDERSTORMS INCREASING IN NUMBER AND INTENSITY AHEAD

OF UPPER LOW MOVING EWD ACROSS MO.  SUFFICIENT DEEP LAYER SHEAR

COUPLED WITH MLCAPES TO 1000 J/KG TO SUPPORT SEVERE THUNDERSTORMS.

PRIMARY THREAT WILL BE LARGE HAIL AND LOCALLY DAMAGING DOWNBURST

WINDS AS STORMS MOVE/DEVELOP EWD.



AVIATION...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 450. MEAN STORM

MOTION VECTOR 25025.





...HALES

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