Frost/freeze potential in northern Illinois Friday night

 

We've enjoyed quite the stretch of mild and mostly dry fall weather over the last week to week and a half, but a return back to reality and more of an 'October-like' feel will greet us by the end of the week.

For the remainder of Tuesday evening, we'll see a mix of sun and clouds as a few weaker upper-level disturbances move across the Midwest. A couple of those disturbances have produced a few showers and thunderstorms west and south of the Stateline. The shower activity across central Illinois isn't anything we need to be concerned with and will mainly remain to the south. But the cluster of thunderstorms moving through northeast Iowa will continue on their northeast trek, reaching southern Wisconsin around 7pm-8pm. Additional isolated thunderstorms will remain possible across northern Illinois after 8pm-9pm.

Wednesday will feature more clouds than sun which will hold afternoon temperatures in the mid-60s. Winds will turn to the north and northeast. Widespread rain returns Thursday with increasing moisture and low pressure sliding just to our south. Northern Illinois will remain north of the low which will keep afternoon temperatures in the 50s and low 60s, but south of the low (in the warm sector) afternoon temperatures will climb into the 70s and 80s.

Following the passage of the low a strong cold front will sweep across the Midwest and western Great Lakes Friday morning. This will pull a considerably cooler air mass down into the Stateline Friday afternoon. Afternoon temperatures will fall through the 50s, remaining in the 50s, during the afternoon. This will also come with a rather strong north wind with gusts 30-40 mph. Following some of the record heat from Monday afternoon it will feel rather chilly Friday afternoon.

By Friday night the winds will ease some as high pressure slides a little close to the Stateline. This will cause temperatures overnight Friday into Saturday to plummet down into freezing territory Saturday morning. This could lead our first fall frost/freeze this season.

As the mercury drops it'll be pretty much right on target for when we typically average our first fall freeze, which for Rockford is around the 13th of

October. Last year the temperature fell to 30 degrees on October 23rd. The earliest fall freeze was back on September 13, 1975, and the latest was the 11th of November back in 2016.