Forecasters are warning as much as 6 inches of snow could fall across the region by Saturday afternoon.
Lake, Porter, Newton, Jasper and Will counties are under a winter weather advisory until noon Saturday.
In Cook County, the winter weather advisory is in effect until 6 p.m. Saturday. Southern portions of Cook County are expected to get 4 to 6 inches of snow by late Saturday afternoon and north and central portions, including Chicago, can expect 2 to 4 inches.
LaPorte County's winter weather advisory also is in effect until 6 p.m. Saturday, with 3 to 5 inches of snow possible on the northwest corner of the county and 5 to 8 inches possible to the southeast.
LaPorte County might experience lake-effect snow late Saturday night into Sunday as well.
Snowfall rates of up to a half an inch per hour are possible after midnight.
Reduced visibility and snow-covered roads could make travel dangerous, forecasters said.