Freezing temperatures possible Chicago area early Saturday – especially far western counties
The coldest air so far this fall season will sweep into northern Illinois and northwest Indiana Friday night and Saturday morning with temperatures possibly bottoming-out in the upper 20s to lower 30s at many locations. A cold front accompanied by showers and a few thunderstorms will move from west to east across our area Friday with temperatures peaking during the forenoon and falling during the afternoon. Skies will then clear from the west overnight, as the front draws away to the east and much colder air follows.
It will be very cold Chicago area-wide Saturday morning with coldest readings in the 20s likely observed in westernmost counties along and west of Interstate-39 where a Freeze Watch (light blue-shaded area) is currently in effect for later Friday night and Saturday morning. The closer-in counties will probably experience lows in the 30-35-degree range and Frost/Freeze watches/warnings may be necessary for those areas. In the Chicago “heat island” low temperatures will most likely drop into the mid and upper 30s.
Cloud cover and winds will play into the final analysis, so we will have a better handle on the situation later Friday.