

256 

WWUS20 KWNS 181406

SEL1

SPC WW 181406

IAZ000-ILZ000-MOZ000-182100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 341

NWS STORM PREDICTION CENTER NORMAN OK

905 AM CDT FRI JUN 18 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL AND EASTERN IOWA

       NORTHWESTERN ILLINOIS

       NORTHERN MISSOURI



EFFECTIVE THIS FRIDAY MORNING AND AFTERNOON FROM 905 AM UNTIL 400

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 125

STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES WEST

NORTHWEST OF DUBUQUE IOWA TO 50 MILES EAST SOUTHEAST OF LAMONI

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

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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.



DISCUSSION...LINE OF STORMS WITH POTENTIAL FOR EMBEDDED BOWING AND

SUPERCELL STRUCTURES WILL ADVANCE THROUGH IA AND POSSIBLY NRN MO AND

EVENTUALLY INTO NRN IL. STORMS WITHIN THE LINE MAY INTENSIFY AS THE

DOWNSTREAM ATMOSPHERE DESTABILIZES WITH MLCAPE FROM 2000-2500 J/KG

EXPECTED LATER TODAY. PRIMARY THREATS WILL BE DAMAGING WIND AND

LARGE HAIL.



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 27035.





...DIAL

