A dangerous derecho is expected to form in parts of the Northern Plains and Upper Midwest on Monday, with wind gusts over 75 mph likely. A moderate threat for severe storms is in place for parts of South Dakota and Minnesota on Monday afternoon into the evening due to the threat of a derecho, a wind storm that can cause significant damage.

Severe thunderstorms were expected Monday over parts of the Northern Plains as forecasters warned of hurricane-force winds associated with a likely derecho — a fast-moving, long-lasting line of viole...