Chicago area – Freezing Rain Advisory overnight into mid-morning Thursday along and north of Interstate-80 – Dense Fog Advisory until midnight

The Chicago National Weather Service Forecast office has expanded the anticipated Freezing Rain Advisory area (purple-shaded counties on headlined map above) to include all of the Chicago area along and north of Interstate-80 from 9PM CST tonight until 9AM CST Thursday morning. The Dense Fog Advisory (grey-shaded area on the map above) will remain in effect for much of the Chicago area until later this Wednesday evening. 

A cold front will move slowly south through northern Illinois tonight. As the front passes a given location, winds will shift to the north and visibility will improve. At the same time rain will follow and temperatures will fall below freezing behind the front, creating a freezing rain situation that could eventually change to a light freezing drizzle, but continue into Thursday morning. This freezing rain/drizzle could also extend farther south of Interstate-80 as the night progresses, so if you anticipate driving later tonight be aware of potentially slippery/hazardous conditions, perhaps area-wide later tonight/Thursday morning.

Below are maps of the current metro-area weather radar mosaic and visibility values:

Current Metro Weather Radar Mosaic…

Current Metro-area Visibility values (in miles)…