After a couple refreshing, Fall-like, afternoons temperatures are expected to warm in a big way for the weekend. A strong ridge of high pressure out west will gradually shift east, pulling temperatures that have reached the 80s and 90s over the Midwest and Plains, closer to the Stateline Friday and Saturday.
Before we get to the weekend, though, it’ll be another cool and refreshing night with lows falling into the low 50s under mostly clear skies. Winds will remain light as high pressure moves across southern Wisconsin and northern Illinois. The light and variable wind will begin to shift more to the southeast, south and eventually southwest by Friday afternoon and evening. This will bring temperatures into the upper 70s and low 80s for Friday afternoon, with the official high temperature for Friday forecast to rise around 83 degrees.
Southwest winds will increase following the passage of a warm front Friday night, at times gusting close to 30 mph Saturday. This will help bring temperatures into the upper 80s and low 90s, with Rockford’s forecast high to rise around 92 degrees. Dew point temperatures will also increase throughout the day, reaching the mid 60s by the afternoon. This will push the heat index into the low to mid 90s. If high temperatures reach the 90s Saturday it would be the 31st time this year that the high temperature has reached 90 degrees or higher. While that is above the typical amount during any given year, which is around 15 times per year, it’s no where near the record which was 62 days during 1921.
A cold front will be quick to follow Saturday night, remaining nearly stationary near the state line Sunday morning. It’s still a little unclear just how far the front may travel south Sunday which could have a big impact on high temperatures for the afternoon. North of the front temperatures will likely remain in the upper 70s, but south of the front temperatures will warm into the upper 80s and low 90s once again. This could lead to a fairly significant temperature spread from southern Wisconsin, into northern Illinois during the afternoon. By Monday high pressure will work to push the front a little further south before lifting back north Tuesday.