Cool mornings, sunny days, then a midweek weather change

A Look Back:

Three years ago, late August was delivering some of the most dangerous heat of the summer across the Stateline region. Highs soared into the upper 90s, and when combined with tropical humidity, heat index values climbed into the 115 to 120 degree range. Fast forward to this year, and the weather headlines couldn't be more difference. Instead of extreme heat, we're looking at a much more comfortable stretch with afternoon highs in the upper 70s. 

Those upper 70s will come with plenty of sunshine as a weak high pressure system continues to keep a firm grip on our weather pattern. With sinking air limiting cloud development and thunderstorm chances, expect there to be partly cloudy skies. Winds will also be lighter than they were on Sunday, further adding to the day's comfortable feel. As we head into tonight, skies will remain mostly clear thanks to that lingering area of high pressure. That will make for another cool start to the day with mid 50s for most. 

Hit or Miss Chances:

Tuesday remains dry across the Stateline, though we will see signs of our next weather maker by the time we get into the evening. Forecast guidance shows a pocket of upper-level energy or spin tracking into the western Great Lakes by Wednesday afternoon. Ahead of it, we do see moisture spill in as the associated cold front approaches. This may result in the chance for rain after midnight while also fueling the chance for a few thunderstorms on Wednesday.

Because of that setup, the Storm Prediction Center has much of northern Illinois and southern Wisconsin under a level 1 Marginal Risk. It's still a few days away, but it's a setup we'll be keeping a close eye on as details continue to come in focus.