

000 

WWUS20 KWNS 080806

SEL4

SPC WW 080806

IAZ000-ILZ000-081400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 484

NWS STORM PREDICTION CENTER NORMAN OK

305 AM CDT SUN JUN 8 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN IOWA

       EXTREME NORTHWEST ILLINOIS



EFFECTIVE THIS SUNDAY MORNING FROM 305 AM UNTIL 900 AM CDT.



HAIL TO 1.5 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 65 MILES WEST OF DES

MOINES IOWA TO 55 MILES EAST SOUTHEAST OF CEDAR RAPIDS IOWA.  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...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 482. WATCH NUMBER 482 WILL NOT BE IN EFFECT

AFTER 305 AM CDT. CONTINUE...WW 483...



DISCUSSION...A LINEAR MCS IS ORGANIZING NEAR THE MO RIVER AND SHOULD

PERSIST/MOVE EWD INTO CENTRAL/SRN IA THE NEXT FEW HOURS...AND

POSSIBLY ERN IA TOWARD SUNRISE.  A CONTINUED INFLUX OF RICH

LOW-LEVEL MOISTURE FROM THE S/SW WILL HELP SUSTAIN THE

CONVECTION...AND THE OUTFLOW BOUNDARY FROM EARLIER STORMS WILL ALSO

HELP FOCUS THE THREAT AREA IN CENTRAL /SE IA.  THERE WILL BE SOME

THREAT FOR AN ISOLATED/BRIEF TORNADO WHERE THE MCS INTERSECTS THE

OUTFLOW...BUT DAMAGING WINDS AND LARGE HAIL SHOULD BE THE PRIMARY

THREATS THROUGH THE MORNING.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 27040.





...THOMPSON

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