Roads in northwest Illinois had patches of ice and snow on Tuesday and road crews were bracing in northeast Illinois for the storm, which began dropping snow on Chicago near the middle of the morning rush hour.
Chicago was forecast to get 4 to 8 inches of snow, down about 2 inches from a previous forecast, according to the National Weather Service. The heaviest snow was expected Tuesday afternoon in the region, up to 1 inch per hour, and expected to snarl the evening rush hour.
The storm was expected to move eastward over the Ohio Valley and then the central Appalachians and mid-Atlantic states on Wednesday, hitting Washington with its biggest snowfall in possibly two years, the National Weather Service said.
Winter storm warnings were in effect for all or parts of 16 states from the Upper Midwest to the mid-Atlantic on Tuesday, National Weather Service spokesman Chris Vaccaro said.
The storm was forecast to move across Ohio and the Tennessee Valley and merge with a developing storm off the mid-Atlantic states that could produce heavy, wet snow overnight and through Wednesday into the mid-Atlantic states that could bring down trees and power lines, Vaccaro said.