ROCKFORD (WREX) — If you don't want to say goodbye to summer just yet, you're in luck. While Wednesday might be the first full day of autumn, it isn't going to feel like it.
The story of this week's weather pattern focuses on the warmer-than-average temperatures. Highs through midweek climb into the upper 70s and lower 80s, which is nearly 5° to 10° above average. Fall-like temperatures do return next week, but in the meantime, warm temperatures persist.
Wednesday morning brought temperatures into the 50s in most areas under clear skies. The dry atmosphere means a quick warm-up. As a quick weather lesson, increased water vapor results in slower temperature warming. This results in cool mornings and warm afternoons, especially during the fall and spring.
Hazy sunshine is going to continue for midweek, but a few more clouds push into the Stateline thanks to Beta. The remnants of Beta bring heavy rain to the Lower Mississippi Valley and while the rain remains south, the clouds do not.
Clouds build overnight Wednesday into Thursday, leaving behind a partly cloudy to even mostly cloudy sky. This is going to set us up for a slightly cooler day Thursday, with highs still remaining slightly above average. The warmest weather of the week comes in by Friday.
Changes come late in the week:
Thursday features slightly cooler temperatures and an isolated shower or thunderstorm chance. This chance doesn't look very high and in fact, most areas remain dry. A quick-moving disturbance, located over the Northern Rockies early Wednesday, brings a cold front by late Thursday.
As the cold front approaches the Stateline, it's forecast to "washout," or weaken. This means a line of diminishing line of showers or thunderstorms late Thursday evening, especially over far northwest Illinois. The weekend brings slightly higher rain chances to the Stateline.
A more potent cold front brings in rain chances Saturday into Sunday, with more dry time than anything. The recent stretch of dry weather isn't likely to be impacted much by the small rain chances, as it looks like precipitation is going to be isolated.
Cooling off next week:
The first cold front comes in Saturday into Sunday, dropping highs by about 5° by Sunday afternoon. A second and more potent cold front moves through early next week, dropping temperatures into the 60s. Looking at the longer range outlook, it appears that the fall-like temperatures stick around through early October.