Dense fog has dropped visibility to a quarter-mile or less in a few spots, causing slowed and dangerous driving/travel conditions around the Chicago area early this Sunday day morning. At 6AM lowest observed visibilities at airport locations were along and west of the Fox River Valley, but other locations were also affected (see current visibility map below). So if you’re driving early this morning, be prepared to possibly encounter a rapid drop in visibility and perhaps take a little longer to reach your destination.

Surface moisture due to recent rains has allowed the temperature to drop into the lower 60s, matching the dew point and causing condensation in the fog-prone areas. Temperatures will rise and the fog will dissipate in most locations between 8 and 9AM.