WATCHES: Severe Thunderstorm Watch Number 586

WWUS20 KWNS 112320
SEL6
SPC WW 112320
MNZ000-WIZ000-LSZ000-120600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 586
NWS STORM PREDICTION CENTER NORMAN OK
620 PM CDT SAT AUG 11 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

EASTERN AND SOUTHERN MINNESOTA
WESTERN AND NORTHERN WISCONSIN
LAKE SUPERIOR

EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 620 PM
UNTIL 100 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 95
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 65 MILES SOUTH
SOUTHEAST OF KENNEDY WISCONSIN TO 45 MILES WEST NORTHWEST OF
MANKATO MINNESOTA. 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...ISOLATED THUNDERSTORMS HAVE BEGUN TO FORM IN EXTREMELY
UNSTABLE AIR MASS OVER CENTRAL MN. THESE STORMS ARE EXPECTED TO
BECOME SEVERE AND SPREAD EAST-SOUTHEASTWARD INTO WESTERN WI DURING
THE EVENING HOURS. EFFECTIVE SHEAR VALUES ARE FAVORABLE FOR
SUPERCELL STORM STRUCTURES CAPABLE OF DAMAGING WINDS 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 600. MEAN STORM
MOTION VECTOR 28030.

..HART

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