According to Wikipedia,

A derecho (/dəˈr/, də-ray-choh, from Spanish: derecho [deˈɾetʃo], “straight”) is a widespread, long-lived, straight-line windstorm that is associated with a fast-moving band of severe thunderstorms.

The area of the United States under close watch is the center part of the country. Check this out from the Weather Channel here!

Last year I wrote about this weather pattern.