Dense fog covered the Chicago area Wednesday morning.
The fog made visibility difficult for commuters across the metropolitan area for several hours during the morning rush hour.
The fog dissipated by the late morning and early afternoon hours. A Dense Fog Advisory expired at 11 a.m. for Cook and Lake Counties.
Visibility was reduced to a quarter mile or less, especially near Lake Michigan, officials said.
Forecasters warned the fog would make travel hazardous in some places during the morning rush hour, including parts of Lake Shore Drive.
While the advisory was only issued for Cook and Lake Counties, meteorologists said visibility would be reduced across much of the Chicago area.
Temperatures stayed cool during throughout the morning, but the area is expected to see a significant warmup with temps reaching into the 80s by Thursday, possibly breaking a record in the city.