Patchy dense fog has formed across portions of east central Illinois
in the last couple of hours. Visibility may fall below one-quarter
mile at times through this evening, leading to potentially hazardous
travel conditions.
Expect rapid changes in visibility over short distances, with visibility
possibly even near zero at times.
Be sure to slow down if you encounter dense fog. Use low beam headlights if
driving, and leave plenty of distance between you and the vehicle ahead.