

820 

WWUS20 KWNS 231554

SEL0

SPC WW 231554

ILZ000-KYZ000-MOZ000-232300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 340

NWS STORM PREDICTION CENTER NORMAN OK

1055 AM CDT MON MAY 23 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST ILLINOIS

       WESTERN KENTUCKY

       EASTERN MISSOURI



EFFECTIVE THIS MONDAY MORNING AND EVENING FROM 1055 AM UNTIL 600

PM CDT.



HAIL TO 2 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 85

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES WEST

SOUTHWEST OF FORT LEONARD WOOD MISSOURI TO 10 MILES NORTH OF

CARBONDALE ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 337...WW 338...WW 339...



DISCUSSION...MCS WITH WELL-DEFINED MCV IS EXPECTED TO RE-INTENSIFY

THIS AFTERNOON AS IT PROGRESSES EWD AND ENCOUNTERS AN INCREASINGLY

MOIST AND UNSTABLE AIR MASS ALONG THE MS RIVER WITH MLCAPE

INCREASING TO 2000-3000 J/KG.  THIS INSTABILITY COUPLED WITH A DEEP

WSWLY WIND FIELD WILL SUPPORT FORWARD-PROPAGATION OF MCS WITH THE

PRIMARY HAZARDS BEING CORRIDORS OF WIND DAMAGE AND LARGE HAIL.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

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

MOTION VECTOR 27035.





...MEAD

