It’s been quite a while since I’ve written these words in a blog post, but you may want to grab a light jacket if you’re heading out the door early on this morning. Say what now? It’s a crisp and cooler start to our day, with temperatures for a few digging into the upper 40s, including Rochelle and Freeport.
This morning was a textbook example of a weather process we call “Radiational Cooling”. As an area of high pressure slowly moved closer to the region, skies remained mostly clear overnight, and winds for the most part were pretty calm. This allowed temperatures across the region to “bottom out” or rapidly drop for the second morning in a row. Now, if you’re someone who is just enjoying this fall-like stretch, another refreshing afternoon is ahead. But, if you want the summer-like heat to return, you’re in for a treat as we head into the upcoming weekend.
As this area of high pressure enters central Illinois this morning, winds locally are going to shift to the west-southwest by this afternoon. This is going to pull in slightly more warmth and moisture to the region, resulting in a few more clouds for the later half of the day. But despite the extra clouds hovering around, our Wednesday remains dry as high pressure is still firmly in place. Highs top out in the upper 70s, which is still considered “seasonably cool” for this time of year. As for the rest of the work week, rain chances remain very low, but there is a slight chance for an isolated shower during the afternoon on Thursday. The one thing you will notice as we approach the weekend is an uptick and temperatures and humidity. Temperatures look to climb closer to normal by Friday, with highs topping out in the low 80s.
As for the upcoming weekend, a lift in the jet stream will allow a significantly warmer, & humid air-mass to slide in, bringing back that feeling of summer. Forecast high temperatures are expected to top out in the upper 80s by Saturday, and around the 90° mark by Sunday. Humidity is also expected to climb, as dew points end up in the low to mid 70s for both days.
If my math is correct, that will allow heat indices to approach or even eclipse the 90° mark, especially on Sunday. If you have any outdoor plans for the weekend, it looks to be a good one to get some time in the pool to stay cool. You’ll just need to keep an eye on the radar if heading outdoors. With the return of that summertime heat, also brings our best chance for a few thunderstorms throughout the next 7 days. Chances remain hit or miss. But remember, when thunder roars, go indoors.