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WWUS20 KWNS 041735

SEL0

SPC WW 041735

MNZ000-WIZ000-LSZ000-050100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 460

NWS STORM PREDICTION CENTER NORMAN OK

1235 PM CDT WED JUL 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST MINNESOTA

       EXTREME NORTHWEST WISCONSIN

       LAKE SUPERIOR



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 1235 PM UNTIL

800 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 80 MILES WEST

NORTHWEST OF HIBBING MINNESOTA TO 30 MILES EAST SOUTHEAST OF

SILVER BAY MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 459...



DISCUSSION...THUNDERSTORM CLUSTER ACROSS N CENTRAL MN WILL LIKELY

PERSIST AND MOVE/DEVELOP SEWD ALONG THE SURFACE WARM FRONT THROUGH

THE AFTERNOON.  STRONG INSTABILITY IS PRESENT ALONG AND S OF THE

BOUNDARY...WHERE SURFACE HEATING IS ERODING CONVECTIVE INHIBITION.

THUS...ADDITIONAL STORM DEVELOPMENT WILL ALSO BE POSSIBLE SWD ALONG

THE GUST FRONT TRAILING FROM THE ONGOING STORMS.  GIVEN THE STRONG

INSTABILITY AND MODERATE VERTICAL SHEAR ALONG/N OF THE FRONT...A MIX

OF MULTICELL/SUPERCELL STRUCTURES CAN BE EXPECTED EARLY IN THE STORM

FORMATION...WITH SOME POTENTIAL FOR UPSCALE GROWTH INTO A LARGER

BOWING SEGMENT LATER THIS AFTERNOON.  DAMAGING WINDS AND LARGE HAIL

WILL BE THE MAIN SEVERE THREATS.



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 29030.





...THOMPSON

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