SPC MESOSCALE DISCUSSION 1228 FOR CENTRAL MN..NRN/CENTRAL WI..WRN
U.P. OF MI
CONCERNING...SEVERE THUNDERSTORM POTENTIAL...SEVERE THUNDERSTORM
WATCH 442...

VALID 181209Z - 181400Z

NEW WW WILL LIKELY BE ISSUED SOON EAST OF WW 442 ACROSS NRN WI INTO
FAR SRN PORTIONS OF THE U.P. OF MI.

AXIS OF MODERATE INSTABILITY CONTINUES TO SPREAD NEWD ALONG EDGE OF
STRONG CAP...INTO CENTRAL MN AND WRN WI.  MUCAPES OVER THIS AREA
REMAIN IN THE 2000-3000 J/KG RANGE.  AS LLJ SHIFTS SLOWLY ENEWD
ACROSS THE NRN MS VALLEY...FOCUS FOR DEEP CONVECTION WILL LIKEWISE
MOVE INTO CENTRAL/NRN WI AND INTO THE NRN GREAT LAKES.  

CAP APPEARS TO BE DELINEATED BY NW-SE ORIENTED ARC OF CONVECTION
JUST EAST OF THE MS RIVER.  THIS ACTIVITY IS LIFTING NEWD...AND
WILL BE MERGING WITH ORGANIZED ACTIVITY WITH A HISTORY OF LARGE
HAIL SHIFTING ESEWD OUT OF CENTRAL MN.  SECOND AREA OF SEVERE
CONVECTION IS PERSISTING OVER SIBLEY AND NICOLLET COUNTIES IN
MN...AND IS MOVING NEWD AT 45 KT.  EXTRAPOLATION PLACES THIS
ACTIVITY NEAR THE MSP AREA AROUND 13Z.  GIVEN THE STEEP LAPSE RATES
AND DEGREE OF ELEVATED INSTABILITY...THE THREAT OF VERY LARGE HAIL
AND ISOLATED WIND DAMAGE WILL CONTINUE ACROSS THIS REGION.

..EVANS.. 06/18/01