Severe Thunderstorm Watch 396

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 396
NWS STORM PREDICTION CENTER NORMAN OK
500 PM CDT FRI MAY 30 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHEAST IOWA
SOUTHEAST MINNESOTA
SOUTHWEST WISCONSIN
EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 500 PM UNTIL 900
PM 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 45
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES WEST
SOUTHWEST OF ROCHESTER MINNESOTA TO 65 MILES SOUTHEAST OF LA
CROSSE WISCONSIN. 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.
DISCUSSION...SCATTERED THUNDERSTORM CLUSTERS WILL SPREAD ESEWD FROM
MN INTO IA/WI IN ADVANCE OF A MID LEVEL SHORTWAVE TROUGH MOVING
ESEWD OVER THE UPPER MS VALLEY. MODERATE SURFACE-BASED INSTABILITY
AND EFFECTIVE BULK SHEAR OF 40-50 KT COULD SUPPORT A FEW ORGANIZED
STORMS...INCLUDING SOME WITH SUPERCELL STRUCTURES...CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. THE SEVERE THREAT SHOULD
DIMINISH A LITTLE AFTER SUNSET AS THE BOUNDARY LAYER STABILIZES.
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 24035.
..THOMPSON
Iowa counties - ALLAMAKEE, CHICKASAW, CLAYTON, FAYETTE, FLOYD, HOWARD,
WINNESHIEK
Wisconsin counties - CRAWFORD, GRANT
Minnesota counties
FILLMORE, HOUSTON, MOWER, OLMSTED,
WINONA
Wisconsin counties
LA CROSSE, VERNON