Chicago under winter weather warning: Wind-whipped snow much of the day, temps dropping 20 to 30 degrees, glazed roads

A powerful Arctic front is expected to drop 3 to 6 inches of snow, most of that on Thursday afternoon and evening, according to the National Weather Service. (John White | Sun-Times)

A winter weather warning has been issued for the Chicago area Thursday when wind-whipped snow is expected to fall much of the day, temperatures will drop 20 to 30 degrees within hours, and bridges and overpasses could suddenly freeze over.

The warning went into effect at 9 a.m. in Kane, McHenry, Kendall, Grundy, Winnebago, Boone, McHenry, Ogle, Lee, DeKalb, Livingston and LaSalle counties, and was due to start at noon in Cook, DuPage, Will, Kankakee, Iroquois and Ford counties.