National Weather Service United States Department of Commerce

Overview: Winter Storm January 10-11, 2020

A large potent storm system worked its way across the central part of the country on the weekend of January 10th and 11th. This system brought severe thunderstorms and heavy rains across the southern Midwest down to the Gulf Coast, while it brought two rounds of winter weather across southern Wisconsin.

The first round of winter weather began Friday evening as a surface low moved across central Illinois. This brought a mix of wintry precipitation across central and southern Wisconsin through Friday night. There was a distinct cutoff between precipitation type from line from Monroe to Port Washington. For areas to the north of this line, they initially saw a wintry mix of freezing rain, graupel, and ice pellets which formed a thin layer of ice between a few hundredths of an inch up to 0.2 inches, but eventually transitioned to mostly snow by late evening. Anywhere from around an inch up to 3 inches of snowfall was observed through midnight. On the other hand, areas south and east of the line remained at or just above freezing and experienced rain initially and then changed to freezing rain overnight. Areas south of the line from Monroe to Port Washington observed ice accumulations around 0.1 inch up to around 0.3 inches. These wintry conditions created hazardous travel that continue into Saturday morning across southern Wisconsin as some light wintry precipitation of freezing drizzle and light snow lingered through the morning off the Lake.

In addition to the wintry weather, strong northeasterly onshore winds developed across the area Saturday. These strong winds with gusts around 40-50 mph combined with the record high Lake Michigan water levels resulted in significant lakeshore flooding, especially for areas along Milwaukee's lakefront.  

By Saturday afternoon, the upper-level trough pushed into the region and the second round of winter weather began producing light to moderate snow across the southern Wisconsin. Although, initial forecasts called for higher snowfall totals, a easterly shift in the track of the surface low limited snowfall for areas west of a line from Fond du Lac down to Monroe. This shift also kept snowfall amounts on the lower end east of the line with anywhere around 1 inch up to around 4 inches. The heaviest snows occurred along a line just south of Sheboygan down to Waukesha.


2 Day Snowfall Totals 
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