

000 

WWUS20 KWNS 072147

SEL7

SPC WW 072147

IAZ000-ILZ000-MOZ000-080400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 567

NWS STORM PREDICTION CENTER NORMAN OK

445 PM CDT TUE AUG 7 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN IOWA

       EXTREME NORTHWEST ILLINOIS

       NORTHERN MISSOURI



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 445 PM UNTIL

1100 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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST OF

LAMONI IOWA TO 25 MILES NORTH OF BURLINGTON IOWA.  FOR A COMPLETE

DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE

(WOUS64 KWNS WOU7).



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 565...WW 566...



DISCUSSION...SUBTLE SHORTWAVE TROUGH/MCV SHOULD INCREASE STRONG TO

SEVERE THUNDERSTORMS NEAR SURFACE FRONT EXTENDING FROM NERN KS/FAR

NWRN MO INTO E-CENTRAL IA THIS EVENING.  AIR MASS IS EXTREMELY

UNSTABLE WITH MODEST DEEP LAYER SHEAR.  EXPECT A FEW SUPERCELLS NEAR

THE FRONT... WITH OVERALL EVOLUTION INTO MULTICELL CLUSTERS/POSSIBLE

MCS BY THE MID TO LATE EVENING.  LARGE HAIL AND DAMAGING WINDS ARE

EXPECTED WITH THE MORE INTENSE STORMS...IN ADDITION TO VERY HEAVY

RAINFALL RATES.



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 27020.





...EVANS

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