If driving, slow down, use your headlights, and leave plenty of distance ahead of you.

DENSE FOG ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO 10 AM CST WEDNESDAY... * WHAT...Visibility one quarter mile or less in dense fog. * WHERE...Portions of north central and northeast Illinois. * WHEN...From 6 PM this evening to 10 AM CST Wednesday. * IMPACTS...Hazardous driving conditions due to low visibility. * ADDITIONAL DETAILS...Dense fog is expected to develop this evening and continue through Wednesday morning. The lingering cold ground may allow some slick spots on untreated surfaces late tonight outside of Chicago.