A slow-moving winter storm will bring two days of wintry weather to the Midwest starting tonight. Up to 6 to 10" of snow is forecast across Minnesota and Wisconsin. A deep upper-level trough and a push of cold air will bring snow to the Upper-Midwest Today and tomorrow. Strong winds may lead to blizzard conditions, especially across the Dakotas. Light freezing rain is also possible. Periods of moderate to heavy snow to likely in parts of the Midwest through Friday night. Snow accumulations of 6-10" are likely in parts of Wisconsin and Minnesota and northern Iowa.
Strong winds will accompany this snowfall. Winds could gust to as high as 50mph with stronger wind gusts to the west with those high wind warnings with gust up to 70mph today as a strong pressure at the surface and contour gradient aloft will allow for turbulent mixing of winds down to the surface allowing for some strong wind gusts.
Blizzard warnings are in effect for parts of South Dakota, Minnesota, and Iowa due to those strong winds which will cause some blowing or drifting snow to reduce visibility to less than 0.25 miles in these areas for 3 hours or more.
Light freezing rain accumulation of a few hundredths of an inch are also possible today across eastern Minnesota, Iowa, and Wisconsin. An upper-level trough positioned over the northern Plains this morning will continue to amplify as a potent shortwave digs southeast across the central Plains into the mid-Mississippi Valley today, with a closed low developing to the north across the upper Mississippi/ upper Midwest by late in the day.
Warm advection precipitation currently moving east from the Dakotas is expected to fall as a wintry mix across portions of the upper Mississippi valley this morning, before changing over to all snow as cold air aloft arrives. A weakening occlusion to the north of a redeveloping surface low centered over southeastern Minnesota and southwestern Wisconsin is expected to help focus light snows across northern Minnesota into late today. As the upper low continues to deepen, heavier snows are expected to develop within the associated deformation band setting up across southern Minnesota, Wisconsin, and Iowa by late Thursday into the overnight.
The latest WPC PWPF shows high probabilities for snow accumulations of 4-inches or more covering a large portion of southern Minnesota into western Wisconsin and northern Iowa.
The system is expected to gradually weaken and move east on Friday. However, some portions of the area, particularly southern Minnesota and Iowa, could see at least a few more inches before the system departs. The closed low from the Midwest will broaden and begin to lift east/northeast Friday into Saturday, spreading waves of precipitation eastward both along the front and associated with vorticity impulses rotating around the center.
The primary surface low is expected to occlude over Michigan, with a secondary wave developing farther to the east along with the triple point as it undergoes triple point cyclogenesis, centered near New Jersey/Long Island by early Saturday. Steepening lapse rates beneath the mid-level vortex max will combine with waves of energy to produce periods of snow showers over the central Appalachians, with increasing northwest flow driving upslope flow into the favored windward slopes of the central to the southern Appalachians. This is likely to produce accumulations of at least an inch or two across portions of the favored terrain. Further east, warm air advection precipitation spreading ahead of the secondary low will move across upstate New York and New England. General model consensus shows the low tracking near the Vermont-New York border -- supporting mostly snow across the Adirondacks, while most areas across northern New England can expect some transition to rain on Saturday.