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589 

WWUS20 KWNS 040907

SEL4

SPC WW 040907

IAZ000-ILZ000-MOZ000-041500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 654

NWS STORM PREDICTION CENTER NORMAN OK

410 AM CDT TUE AUG 4 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME SOUTHERN IOWA

       WEST CENTRAL ILLINOIS

       NORTH CENTRAL AND NORTHEAST MISSOURI



EFFECTIVE THIS TUESDAY MORNING FROM 410 AM UNTIL 1000 AM 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 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES NORTH OF

SAINT JOSEPH MISSOURI TO 45 MILES EAST SOUTHEAST OF QUINCY

ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 653...



DISCUSSION...A GROWING CLUSTER OF THUNDERSTORMS ACROSS NW MO HAS THE

POTENTIAL TO DEVELOP A COLD POOL AND ACCELERATE EWD/SEWD THROUGH THE

MORNING ACROSS NRN MO...WITH AN ACCOMPANYING RISK FOR DAMAGING

WINDS.  LARGE HAIL WILL ALSO BE POSSIBLE ACROSS THE WATCH AREA GIVEN

THE PRESENCE OF STEEP MID LEVEL LAPSE RATES AND MUCAPE OF 3000-4000

J/KG.



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 550. MEAN STORM

MOTION VECTOR 28030.





...THOMPSON

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