The National Weather Service upgraded its winter storm watch in northern Illinois to a warning early Thursday morning, meaning a lengthy and heavy snowfall is likely from Thursday night to Friday night.
The warning is in effect from 6 p.m. Thursday through 9 p.m. Friday, and six to 10 inches of snow are possible — some places may even see up to 12 inches.
"Travel will be very difficult to impossible at times, including during the morning commute on Friday," the alert stated.
Visibility will also likely be affected. The service encouraged motorists not to travel unless completely necessary and to keep an extra flashlight, food and water in the vehicle, in case of an emergency.