With temperatures and dew-points nearly identical, patchy dense fog has developed early this Tuesday morning mainly in western portions of the Chicago area along the Fox River Valley and along and west of Interstate-39. Areas of lowest visibility are displayed on the map below.
If driving this morning be aware that patches of fog could quickly see visibility drop below a quarter-mile in spots, so be prepared.
Fog should lift with visibility improving area-wide by 8AM CST.
Map displaying current visibility…