National Weather Service: December 15th Storm System Was A Derecho

(Undated) -- The storm that blew across the Midwest last week is being called a derecho. The National Weather Service says the December 15th, 2021 derecho was the first to occur anywhere in the U.S. in the month of December. The National Weather Service says the storm was a serial derecho, meaning it was part of a large-scale weather system. Last week's derecho had lower wind gusts than the one that happened in August 2020, which was a progressive derecho. That means it was part of a more localized system. In order for a storm to be considered a derecho it must travel at least 240 miles and consistently produce wind speeds up to 58 MPH. The National Weather Service says derechos also usually have wind gusts above 75 MPH.