Chicago Weather: Frosty Night For Some; Temperatures Dip 15 Degrees Below Normal Friday

CHICAGO (CBS) -- It will be a frosty Thursday night for areas of Northern Illinois and Southern Wisconsin as the coldest air of the season settles in.

The frost advisory includes McHenry County, Boone, and Winnebago counties in Illinois, as well as most of Wisconsin north all the way through Wausau and Green Bay. Parts of Wisconsin, including Eau Claire, have a freeze warning starting at 1 a.m.

Showers will be wrapping up, but lake-effect rain will persist in Northwest Indiana.

Forty-one will be the low at O'Hare International Airport, while McHenry could dip to 34.

Friday brings sunshine and the mid-50s, a typical temperature for early November. The normal high should be upper 60s.

Sunrise Friday is at 6:50 a.m.