

000 

WWUS20 KWNS 111019

SEL8

SPC WW 111019

IAZ000-MNZ000-111700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 508

NWS STORM PREDICTION CENTER NORMAN OK

515 AM CDT WED JUN 11 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST AND NORTH CENTRAL IOWA

       WEST CENTRAL...CENTRAL AND SOUTHWEST MINNESOTA



EFFECTIVE THIS WEDNESDAY MORNING FROM 515 AM UNTIL NOON 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 65

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES WEST

NORTHWEST OF SAINT CLOUD MINNESOTA TO 30 MILES SOUTH SOUTHEAST OF

STORM LAKE IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 507...



DISCUSSION...ELEVATED STRONG TO SEVERE THUNDERSTORMS CONTINUE TO

DEVELOP FROM ERN SD SWD INTO THE MID-MO VLY ALONG THE FRINGE OF

MODEST CAP.  LLJ WAS BEGINNING TO VEER TO SWLY WITH 60 KTS NOTED AT

THE NELIGH PROFILER IN NE NEB.  AS THE STRONGEST WARM ADVECTION

REGIME SHIFTS EWD WITH TIME...SO SHOULD TSTM DEVELOPMENT.  STEEP

MID-LEVEL LAPSE RATES AND EFFECTIVE SHEAR OF 45-50 KTS WILL BE

FAVORABLE FOR ORGANIZED STORMS CAPABLE OF LARGE HAIL.

FURTHERMORE...DMGG WINDS WILL BE LIKELY AS WELL DESPITE ELEVATED

NATURE TO THE STORMS OWING TO UNSATURATED MID-LEVELS AND RESULTANT

DCAPE VALUES.



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 26030.





...RACY/THOMPSON

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