A combination of dangerous winter weather will be in effect for portions of the Chicago area along and just south of Interstate-80 north to the Illinois-Wisconsin state line as a strong low pressure system moves through from west to east.
From this Sunday evening overnight into Monday morning, heavy snow and blowing snow is expected over this same area. A Winter Storm Warning (pink-shaded on headlined map) for 6 to 9-inches of snow and blowing snow is in effect in Illinois counties generally bordering Wisconsin. Heavier snow is expected farther north into Wisconsin.
A Winter Weather Advisory (purple-shaded area) for 3 to 6-inches give or take an inch or so of snow and blowing snow is forecast with a gradation of heaviest snow north to the least across far southern portions of the Winter Weather Advisory. Areas farther south of the Warning/Advisory will experience a light wintry mix of wind, perhaps an inch or two of snow, rain, drizzle and eventually falling temperatures.
Heavy snow should diminish Monday morning, but hazardous travel and outdoor conditions should continue with periods of possibly some freezing drizzle and then snow showers along with blowing snow, as colder air follows into the area behind the departing low pressure. Snow showers/flurries should end from west to east Monday night.
Regional Weather Radar Mosaic...