

930 

WWUS20 KWNS 231701

SEL8

SPC WW 231701

IAZ000-MNZ000-232300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 498

NWS STORM PREDICTION CENTER NORMAN OK

1200 PM CDT TUE JUN 23 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN INTO CENTRAL IOWA

       SOUTHERN MINNESOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM NOON UNTIL 600

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 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 10 MILES WEST OF

SPENCER IOWA TO 55 MILES NORTHEAST OF WATERLOO IOWA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU8).



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 495...WW 496...WW 497...



DISCUSSION...LONG-LIVED COMPLEX OF THUNDERSTORMS MOVING OUT OF THE

CENTRAL PLAINS SHOULD CONTINUE GENERALLY EWD AT 35-40 KT ALONG

COMMON OUTFLOW INTO EXTREME INSTABILITY IN PLACE ACROSS WW.

DAMAGING WINDS COULD BECOME MORE ORGANIZED THIS AFTERNOON AS COLD

POOL INTENSIFIES...WITH LARGE HAIL POSSIBLE WITH THE STRONGER CORES.



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 500. MEAN STORM

MOTION VECTOR 27035.





...EVANS

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