

000 

WWUS20 KWNS 212050

SEL6

SPC WW 212050

IAZ000-ILZ000-220000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 436

NWS STORM PREDICTION CENTER NORMAN OK

350 PM CDT THU JUN 21 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN AND CENTRAL IOWA

       A SMALL PART OF NORTHWEST ILLINOIS



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 350 PM UNTIL

700 PM CDT.



HAIL TO 3 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 35

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 70 MILES WEST OF DES

MOINES IOWA TO 15 MILES SOUTH SOUTHEAST OF MOLINE 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 433...WW 434...WW 435...



DISCUSSION...MCS WITHIN WW 434 IS BUILDING SWD INTO THE I80 CORRIDOR

ACROSS CENTRAL IA LATE THIS AFTERNOON.  AIR MASS REMAINS VERY

UNSTABLE AND SHOULD SUSTAIN THREAT OF SEVERE ACROSS THIS AREA INTO

THE EARLY EVENING.



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

TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 28035.





...EVANS

