UPDATE: The National Weather Service has issues a Winter Storm Warning for southern Wisconsin that will begin at 2pm Friday until Saturday evening. This is the area that will see some of the highest snow totals.
Well...its another December weekend and that means another weekend of snow for the Stateline. While details are coming together on who will see the most snow in the Midwest, we will still watch for any changes in current forecast track. If the low strengthens or shifts it's track, snow totals will be affected.
For totals, right now confidence is high on 4+ inches of snow falling north of the Stateline from Madison to the Twin Cities, but for northern Illinois the confidence is a bit lower. The southwest corner of the Stateline has the lowest chance to see accumulating snow over 4".
With the low forecast to track from Kansas to St. Louis and then northeast into Indiana, the highest totals will be just north of the Stateline. 8-12" of snow is possible in Madison to the Twin Cities, and Winter Storm Warnings have been issued just north of the Wisconsin Dells into eastern Minnesota. South of Madison into southern Wisconsin near the Illinois Stateline totals range from about 4-6" on snow. Orangeville to Rockford and then southeast into McHenry county have a better chance at 4-6" of snow. The farther south and west you head, totals will be dropping off. 2-3" is looking favorable for northern DeKalb county, Ogle, and Carroll counties. The lowest totals near an inch will be favored near Dixon and Sterling.
The forecast is tricky though, because the biggest question is how far the warm air will be drawn northward, because the snow in those locations could actually transition over to some sleet and that would undercut snow totals in some locations.
Timing out the snow; we'll watch tonight and early Friday morning with a light snow shower or a few flurries possible. At most a dusting on some surfaces Friday morning. There isn't enough moisture available for a lot of snow, but with continued southwest flow aloft, we will continue to draw in more and more moisture. Warm air advecting into the area will help with broad lift in the Mississippi Valley area and then reaching the Midwest. Friday will notice an increasing snow chance, as warm and moist air spreads over the area. A chance for snow after noon on Friday, but overall more likely late Friday afternoon and through Saturday. It won't snow the entire time, a lull is expected Saturday morning as dry air spills in. But another round of snow expected Saturday afternoon with strong cold air advection behind the cold front. Winds will also be strong from the northwest Saturday and blowing and drifiting snow will be a concern as well. Snow tapers off my Saturday evening.
Make sure to keep checking back for more updates as we continue to fine tune the forecast!