In a month that before Tuesday had featured just three days with temperatures above 75°, the 87° high temperature registered in Rockford today was surely a change of pace! Not only does it easily take the crown as the warmest day of the month thus far, it marks the warmest temperatures we've seen here since early August!
Warmth like today's, while nowhere near record territory, is a bit abnormal this late in the season. An examination of Rockford temperature records dating back to 1906 reveals that just 16 times has the Stateline seen temperatures of 87° or higher on September 10. That equates to this kind of warmth occurring this late in the season about once every seven years!
There's little reason to believe anything will change in the days ahead. We're expecting temperatures to remain in the middle to upper 80s both Wednesday and Thursday, with heat index values reaching between 90° and 95° each afternoon. Should enough sunshine be present on either days, these temperature and heat index projections may be on the conservative side!
Storm chances appear to be confined to two distinct windows in the next few days, the first coming late Wednesday night into early Thursday morning, and the second arriving Thursday Evening. The first round of storms will be capable of producing locally heavy rainfall, while the second would have a better chance for producing locally severe wind gusts.
Brief relief from the heat arrives Friday and Saturday, though temperatures and humidity levels will begin a rapid climb again on Sunday.