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Unsettled Weather in the Eastern U.S. through Memorial Day

Showers and thunderstorms are expected from Texas to the Northeast through Tuesday. Heavy rain will create mainly localized areas of flash flooding across the central Gulf Coast into the Appalachians. Elevated to Critical fire weather conditions due to gusty winds and low humidity are expected through Tuesday across Oregon and Nevada. Showers and thunderstorms will develop over the Northwest. Read More >

Overview

On June 29, 2019 a surface boundary was located across south central South Dakota. Very strong instability along the boundary was realized when a thunderstorm exploded along it. The thunderstorm updraft stretched energy along the boundary into a very slow moving tornado near Allen, SD.

The tornado was visible for many miles. It was unusual because it only moved within a two mile area, but lasted about 40 minutes. Fortunately, it spun over corn fields most of the time. It damaged a house, blew over a couple of grain bins, snapped power poles, and carried grain bags. The tornado was rated EF-1 by an NWS storm survey team.

More information about the environment of the Allen tornado can be found here

Tornado near Allen, SD
Courtesy Chris O.
Tornado near Allen, SD Tornado near Allen, SD Tornado near Allen, SD
Courtesy Gail S. Courtesy Josie D. Courtesy Ang G.
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