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Tracking Severe Thunderstorms and Excessive Rainfall in the Southern U.S.; Winter Storm to Impact the Northern U.S.

A storm system will shift from eastern Texas into the lower Mississippi Valley Monday with additional threats of severe thunderstorms and heavy to excessive rainfall which may bring flooding. A Flood Watch remains in effect. In the northern U.S., a storm will bring heavy snow and gusty winds over parts of the northern Rockies, northern Plains, and Upper Midwest Monday into Wednesday. 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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