The most significant snow event yet this season is expected this evening, and Winter Storm Warnings have already been issued in parts of the area.
The National Weather Service has issued a Winter Storm Warning for counties north and west of Chicago, including DeKalb, McHenry and Winnebago, while a Winter Storm Advisory will be in effect for the remainder of the Chicago Metro area.
Snow will move in from the southwest during the afternoon hours and begin falling around 3-5pm and continue throughout the evening. Areas in the Winter Storm Warning will see snow for the longest duration, while the rest of the area will see snow eventually changing to freezing rain before changing to pure rain after 2-4 am. Rainfall will continue throughout the morning on Wednesday before ending around noon.
Snow accumulations will greatly favor far northwest sections, including the DeKalb and Rockford areas, with 4-7″ expected. Totals will diminish southward, with an average of 2-4″ throughout most of the immediate Chicago area, and only 1-2″ along and south of the I-80 corridor, where snow will switch to rain earliest and limit snow totals.