

446 

WWUS20 KWNS 021729

SEL1

SPC WW 021729

ILZ000-INZ000-KYZ000-MOZ000-030100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 321

NWS STORM PREDICTION CENTER NORMAN OK

1225 PM CDT TUE JUN 2 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN ILLINOIS

       EXTREME SOUTHWESTERN INDIANA

       FAR NORTHWESTERN KENTUCKY

       EASTERN MISSOURI



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1225 PM UNTIL

800 PM CDT.



HAIL TO 1.5 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 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 60 MILES SOUTH

SOUTHWEST OF QUINCY ILLINOIS TO 55 MILES SOUTHEAST OF MATTOON

ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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...STORMS ARE DEVELOPING AHEAD OF UPPER LEVEL IMPULSES

LOCATED IN FAR SERN IA AND SWRN MO. AIR MASS HAS BECOME MODERATELY

UNSTABLE AND MLCAPES WILL APPROACH 3000 J/KG BY LATE AFTERNOON. THIS

INSTABILITY ALONG WITH 20-30 KT DEEP LAYER SHEAR WILL FAVOR SEVERE

MULTICELL SEVERE STORMS WITH HAIL AND DAMAGING WINDS.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 24020.





...IMY

