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WWUS20 KWNS 012327

SEL2

SPC WW 012327

IAZ000-ILZ000-KSZ000-MOZ000-020700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 242

NWS STORM PREDICTION CENTER NORMAN OK

625 PM CDT TUE JUN 1 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHEAST AND EAST CENTRAL IOWA

       EXTREME NORTHWEST AND WEST CENTRAL ILLINOIS

       EXTREME NORTHEAST KANSAS

       NORTHERN MISSOURI



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 625 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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES WEST

SOUTHWEST OF FALLS CITY NEBRASKA TO 25 MILES NORTHEAST OF

BURLINGTON IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 241...



DISCUSSION...UPSCALE GROWTH OF CONVECTION AND COLD POOL NEAR OMAHA

APPEARS TO BE THE EARLY STAGES OF A BOWING MCS THAT WILL LIKELY MOVE

ESEWD/SEWD THROUGH EARLY TONIGHT TOWARD NRN MO.  THIS CONVECTION

WILL BE MAINTAINED BY A CORRIDOR OF STRONG INSTABILITY AND MODERATE

LOW-MIDLEVEL FLOW OUT OF THE W/SW...AND THE PRIMARY SEVERE THREATS

WILL TRANSITION TO DAMAGING WINDS AND LARGE HAIL.  SOME

BACK-BUILDING STORMS SHOULD SPREAD INTO NE KS...AND MORE ISOLATED

STORMS ALONG THE MOISTURE/INSTABILITY GRADIENT WILL SPREAD ACROSS SE

IA TOWARD WRN IL THIS EVENING...IN ADVANCE OF THE MCS.



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 29030.





...THOMPSON

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