Heavy snow is expected across a good share of Upper Michigan beginning during the day Wednesday and winding down Thursday morning.
The system responsible for the expected snow is low pressure that will move through South Dakota into southern Minnesota, then into central Wisconsin and finally the eastern Upper Peninsula. This is a ??western?? low-pressure system rather than the traditional ??Colorado?? low that brings heavy snow to the U.P. Western lows are conditional heavy snow producers for us in that, coming from the west, moisture availability can be a problem. However, at this time of the year, it will not be.
At this point the heaviest snows should fall from western Upper Michigan around Ironwood eastward into the central Upper Peninsula around Marquette and Iron Mountain. There, 6 to 12 inches are likely with a few spots in the higher elevations possibly getting a little more. Farther east and south, look for a general 5 to 9 inches with the most in the north toward Munising. Over the eastern U.P. only 2 to 5 inches are expected around Newberry to Manistique. Finally in the far south around Menominee, rain may mix in with the snow later Wednesday night to reduce snow accumulations there to only a couple of inches.
The low will then weaken and drift off to our northeast. Behind it, high pressure will build in with chilly (but not cold) air for later Thursday into Friday. Over the weekend, a westerly flow aloft will lead to a warm up. Once it warms up again, the probability of getting a cold enough system to produce heavy snow will go down significantly as the days get longer and the sun angle gets higher. Of course, taking into account the weather we??ve experienced the last four-and-a-half months, there are no guarantees!