What are the atmospheric conditions that produce derechos?

Weather News

SIOUX CITY, Iowa/Chicago, Illinois (KCAU/WGN) – WGN out of Chicago, Illinois, has a weather blog where viewers send in weather-related questions for Chief Meteorologist Tom Skilling to answer.

John Posulka, a viewer from Wolverine, Michigan reached out to Tom Skilling to ask him about the atmospheric conditions needed to produce a derecho.

Tom Skilling responded to Posulka’s question.

A derecho develops from an organized cluster of thunderstorms that evolves into a bow echo.

Thunderstorm development requires warmth, moisture, instability and lift and bow echoes can form when the winds aloft are strong with little change of direction with height.

As rain-cooled thunderstorm downdrafts strike the surface, they spread out in the direction of the storm movement forming a gust front, generating wind gusts in excess of 60 mph and sometimes in excess of 100 mph.

The storm complex must travel at least 250 miles to be called a derecho and the length of the line can range from about 50 to several hundred miles.

While most derecho damage is from straight-line winds, small tornadoes are often embedded in the storms.

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

Local News

More Local News

Trending Stories