By Kelly Franson
A derecho is a long-lived squall line of thunderstorms that "bows" as it moves forward, meaning you see an arc instead of a straight line on the radar. This leads to widespread straight-line wind damage. By definition, the wind damage swath of a derecho extends at least 240 miles.
Will a derecho form Wednesday? It's very possible in the upper Midwest and Ohio valley, but we won't really know until the system develops. Regardless, severe storms are expected in that area, with wind damage likely, along with possible tornadoes.
In our part of the Carolinas, a stray storm is possible Wednesday, but the bigger story is heat. We're headed for the 90s everywhere outside the mountains. With the humidity, the peak heat indices (what is actually feels like), will peak in the mid to upper 90s.