Clouds will increase during the day Wednesday as two storm systems move towards northern Illinois and southern Wisconsin. Low pressure moving in from the southwest will spread snow from south to north Wednesday afternoon and evening, while a strong cold front from the north will pull down an Arctic air mass during the day Thursday.
Light snow will develop to the south Wednesday afternoon lifting into parts of Lee, DeKalb and Whiteside counties likely by late afternoon. The snow, mostly light, will continue to spread north through the evening and overnight. At the same time, a cold front to the north will move south bringing increasing snowfall with it as well. The snow through the evening Wednesday is expected to remain mostly light, but could cause some slick spots on the roads for the evening commute. Light to moderate snow will continue into Thursday morning as the cold front moves through northern Illinois, into central Illinois. Gusty north winds will increase behind the front with blowing and drifting snow likely through Thursday mid-morning. Slick roads and reduced visibility will be likely through the morning commute, with gusty winds continuing into the afternoon.
Snow accumulations will likely range between two and four inches over most of northern Illinois and south-central Wisconsin, with lesser amounts to the northwest and higher amounts to the southeast.