Update 5:30PM CST...
The Winter Weather Advisory (purple-shaded area on the headlined map) for some light snow accumulation and blowing snow will continue up until midnight this Monday evening. Because the cold temperatures lower the efficiency of salt and other road applications, even a little snow blowing across the roadways can create slick spots. Snow should diminish and end from the west later tonight, but blowing snow could continue, so take extra precautions if traveling even later tonight.
Update 10AM CST...
A Winter Weather Advisory for light snow and blowing snow is in effect for the Chicago area along and just south of Interstate-80 all the way north to the Illinois/Wisconsin state line. The main system snow continues to move off to the east, but difficult and slick travel conditions will exist as a secondary band of a little drier snow moves through from the northwest this afternoon/evening depositing an additional inch or so generally north of Interstate-80. Winds will pick up out of the northwest gusting over 30 miles per hour, carrying much colder air into our area and cause some blowing and drifting of falling snow and that already on the ground.
CHICAGO -- A combination of dangerous winter weather continues in effect today 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.
Heavy snow will be ending from the west this morning, then a trailing band of light snow or flurries as winds gusting over 30 mph shift to the northwest swing through this afternoon and evening with falling temperatures along with some blowing and drifting.
A Winter Storm Warning (pink-shaded on headlined map) for a total of 6 to 9-inches of snow and blowing snow is in effect in Illinois counties generally bordering Wisconsin.
A Winter Weather Advisory (purple-shaded area) for 3 to 6-inches 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 this morning, but hazardous travel and outdoor conditions should continue with periods of first freezing drizzle and then snow showers along with blowing snow and minor accumulations (mainly north of Interstate-80), as colder air follows into the area behind the departing low pressure this afternoon/evening. Snow should end from west to east Monday night
As bitterly-cold arctic-source air flows into the Midwest and Great Lakes, temperatures will steadily fall with life-threatening wind chills expected. The Chicago area-wide Wind Chill Watch for wind chills 50 to 55-degrees below zero takes effect beginning Tuesday evening and continuing through Wednesday and Wednesday night into Thursday morning. National Weather Service trace of expected wind chills below.
Regional Weather Radar Mosaic...