UPDATE, 2:20 p.m.:
A winter weather advisory was just issued for northern Illinois.
The National Weather Service issued the winter weather advisory at 2:05 p.m. The winter storm watch that had been in effect for Thursday is no longer active.
The winter weather advisory will be in effect from 9 a.m. Thursday until 9 a.m. Friday, with snowfall totals of four to eight inches possible.
The first major snowfall of the season is expected to hit northern Illinois Thursday.
The National Weather Service has issued a winter storm watch for all of northern Illinois and most of Wisconsin from Thursday morning through Friday morning.
The snow is expected to start by midday Thursday and continue through Friday morning, with forecast accumulations of six inches or more.
The National Weather Service said residents should also expect winds of 15 to 25 miles per hour, with gusts of up to 35 miles per hour, Thursday evening.
Check out the National Weather Service's multimedia weather briefing.