(CHICAGO) Snow is expected to move over the Chicago region all day Saturday, potentially dropping up to 4 inches in the city and half a foot in the south suburbs and northwest Indiana.

Snowfall began about midnight near Pontiac and is making its way northeast throughout Saturday morning, according to the National Weather Service. O’Hare International Airport is expected to see snow arrive around 10 a.m.

The NWS issued a winter weather advisory for the metropolitan area from 6 a.m. Saturday to 3 a.m. Sunday, warning of snow-covered roads and reduced visibility for drivers.

Areas along and south of I-80 in Illinois and northwest Indiana will be hit the hardest, with up to 8 inches expected there, the NWS said.

Sunday and Monday were expected to be mostly sunny in Chicago, with highs in the low 30s.