A low pressure system will move from the Kansas/Nebraska border region and then take a northeast track as it weakens tonight and Tuesday. This low pressure system will move across southern Wisconsin Tuesday morning.
Increasing south winds ahead of the the low pressure system will bring a rapid increase in atmospheric moisture after midnight tonight. This moisture along with the approaching low pressure system will bring light snow to southern Wisconsin after midnight tonight. The light snow is expected to develop over southwest Wisconsin in the Dodgeville, Darlington, and Reedsburg areas between midnight and 3 am, and then in the Madison, Portage, Kenosha, Milwaukee and Beaver Dam areas between 3 am and 6 am.
Most areas should receive around 1 inch of snow, with locations west of Madison receiving between 1 and 2 inches. The light snow will cause deteriorating travel conditions over southern Wisconsin late tonight and early Tuesday which will have an effect on the morning commute. Tuesday morning motorists should stay abreast of the latest forecast, and plan to allow extra time for your drive to work.
Here is the snowfall forecast for the entire state of Wisconsin for tonight through 1pm Tuesday.
NWS - Milwaukee/Sullivan