

000 

WWUS20 KWNS 260009

SEL6

SPC WW 260009

IAZ000-ILZ000-MOZ000-NEZ000-260700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 606

NWS STORM PREDICTION CENTER NORMAN OK

710 PM CDT WED JUN 25 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND SOUTHERN IOWA

       WESTERN ILLINOIS

       FAR NORTHEAST MISSOURI

       EASTERN NEBRASKA



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 710 PM

UNTIL 200 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 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST OF

TEKAMAH NEBRASKA TO 25 MILES SOUTH 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 605...



DISCUSSION...TSTMS HAVE BEEN FORMING IN THE PAST 90 MINS NEAR

INTERSECTION OF  SLOWLY-MOVING NE/SW COLD FRONT WITH DIFFUSE NW/SE

WARM FRONT IN CNTRL IA.  WARM SECTOR IS VERY UNSTABLE...WITH SBCAPE

AOA 3500 J/KG.  WHILE REGIONAL WIND FIELD AND LARGE SCALE FORCING

FOR ASCENT WILL REMAIN WEAK...COMBINATION OF STRONG INSTABILITY WITH

MODEST DEEP SHEAR AND LOW-LEVEL ASCENT ALONG FRONTS MAY SUPPORT A

FEW SUSTAINED STORMS/BRIEFLY ROTATING STRUCTURES WITH POTENTIAL FOR

BOTH LARGE HAIL AND HIGH WIND.



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 28020.





...CORFIDI

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