

000 

WWUS20 KWNS 140744

SEL6

SPC WW 140744

IAZ000-ILZ000-141200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 596

NWS STORM PREDICTION CENTER NORMAN OK

245 AM CDT TUE AUG 14 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EASTERN IOWA

       NORTHERN AND CENTRAL ILLINOIS



EFFECTIVE THIS TUESDAY MORNING FROM 245 AM UNTIL 700 AM CDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75

STATUTE MILES EITHER SIDE OF A LINE FROM 40 MILES WEST OF

BURLINGTON IOWA TO 35 MILES SOUTH SOUTHEAST OF ROCKFORD ILLINOIS.

 FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 595...



DISCUSSION...BOW ECHO OVER SWRN WI CONTINUES TO MOVE SSEWD AT 40-50

KT.  ACTIVITY IS FOLLOWING ERN EDGES OF INSTABILITY GRADIENT WHERE

MLCAPE IS 1000-2000 J/KG /MUCAPE OF 2000-3000 J/KG/.  BOW SHOULD BE

THE MAIN ACTIVITY OVER THE NEXT SEVERAL HOURS.  ACTIVITY OVER S

CENTRAL WI IS EXPECTED TO MOVE INTO AIR MASS WITH LOWER DEWPOINTS

THAT ARE IN THE MID/UPR 50S.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 32040.





...MCCARTHY

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