Accumulation could range from 3″ to 7″ depending on the track of the storm.
The Wednesday morning commute is likely to be messy as a major storm moves into the area this evening.
According to the National Weather Service in Chicago (NWS-C), rain will turn to light snow around 7pm in the Fox Valley this evening, increasing overnight to potentially 1″ per hour, which will last until Wednesday afternoon at which point it will taper off to light snow Thursday evening.
Expected accumulation is difficult to ascertain as only slight changes in the path of the storm will have large effects on the region. At the moment, snow will likely be greatest in the southern part of the region, but if the storm shifts only slightly northward from its current path, the entire region might face much heavier accumulations.
This chart from NWS-C shows what can be expected given the current path of the storm.