How Chilly?

The coolest air in a long time is poised to move in this weekend. Behind tonight's strong cold front, winds will turn blustery out of the northwest on Saturday. That will do two things. First, it will make for a breezy day. Second, it will keep our high temperatures in the lower 70's under a mostly cloudy sky. That will result in an early October feel, especially early in the day when a few isolated showers are possible. Once the winds subside in the evening and high pressure begins to move in and eat away at our cloud cover, temperatures will be allowed to fall off like a rock.

When you want chilly temperatures in the warm months, you must have ideal conditions. Clear skies, light winds, and an area of high pressure combine to support very effective radiational cooling. These components will all be in place Saturday night, which will allow temperatures to fall into the upper 40's in many spots. Some of our forecast models hint at middle 40's, which wouldn't be completely shocking in our typically cooler locations, such as Rochelle, Freeport, and Monroe. Nonetheless, our average low currently is 55°, and the last time temperatures dropped to 48° or less was back on May 19th! So it'll definitely be an unseasonably cool night for mid-September.