The National Weather Service has issued a winter weather advisory in effect from noon to 9 p.m. Tuesday.
The precipitation will start as snow, possibly mixed with sleet early Tuesday afternoon, then change to all wet snow continuing into the early evening. Snow may be heavy at times.
"There remains a high degree of uncertainty with respect to snow accumulation, however best guess is ... 3 to 6 inches will have fallen by late evening across the advisory area," according to the Weather Service. "There is a slight chance of isolated thundersnow, which could result in isolated totals of over 6 inches. ... Heavy snow is expected to impact the late afternoon commute ... anticipate significantly elevated travel times."
The other complicating factor will be winds up to 40 miles per hour, according to the watch.
"Heavy wind-whipped, wet snow is expected this afternoon and evening, resulting in very low visibilities and difficult travel," according to the NWS.
The watch area includes all of DuPage and Cook counties and the entire Chicago area.
Here's the forecast for the week:
Tuesday: 100 percent chance of snow, high 39 degrees. Tuesday night, 80 percent chance of snow with a low of 34.
Wednesday: Snow is likely to continue (80 percent chance) with a high of 35 during the day and a low of 29 at night.
Thursday: Slight chance of snow, high 35, low 26.
Friday: Chance of flurries, high 32, low 22
Saturday: Partly sunny, high 30