On the second day of a developing heat wave, under a sunny sky, afternoon temperatures reached well into the 90s. Both Clintwood and Nora had 97 degrees. The 97 degrees at Clintwood was the hottest temperature on record there.
Meanwhile, an area of multi-cellular convection had moved out of northern Illinois that morning. It continued to organize and strengthen, as it propagated east and southeast across northern Indiana into western Ohio during the afternoon. As it moved through Ohio, it had already formed into a large arch of storms, or bow, with a developing cool pool in its wake. The temperature contrast between the air ahead of the developing derecho, compared to that in its wake was reaching 30 to 35 degrees. The resultant wind shift in the cool pool resulted in strong moisture convergence on the leading edge of the complex. This in turn, helped drive the storms further southeast, away from the mid and upper level wind support. However, the complex was diving right into that hot air that had obtained large convective available potential energy, on the order of 4000 to 5000 j/kg.
The weakening complex reaching into Buchanan County around 1900E. The outflow, or gust front, had outraced the rain.
Wind gusts of 55 to 65 mph were likely with the leading gust front. In the wake of these stronger winds gust, many areas did not even receive any rain. Grundy reported a meager 0.03 inches. Clintwood and Nora had no rain.
The wind caused trees and large branches to fall in scattered locations. The most impact was on the electric grid, let to a lesser degree than further north in West Virginia. Power outages lasted a few days in some areas. The lack of electricity in the midst of the heat wave, disrupted the daily routines of those citizens for several days. Water and ice were in high demand.