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Cold Front Dropping South Across the Western U.S.; Watching Threat for Tornadoes and Flooding in the South

A cold front will push south across the Western U.S. into Tuesday with mountain snow and areas of gusty to high winds. An area of low pressure will form along this front on Tuesday and bring a potential for severe thunderstorms with tornadoes and excessive rainfall in the lower to mid Mississippi River Valley. To the north, heavy snow is possible in parts of the upper Midwest. Read More >


Thunderstorms erupted over eastern Iowa during the mid afternoon on Tuesday, August 10 in an extremely unstable air mass over the region. Clusters of thunderstorms continued to track and develop across northern Illinois into northwest Indiana through the evening hours, producing areas of notable wind damage.


Another cluster of thunderstorms developed over Iowa during the early morning hours of Wednesday, August 11 and became more organized as it tracked into northern Illinois. These storms ended up producing a broad swath of wind damage to trees and crops across northern Illinois that started in Lee and LaSalle counties and extended into the Rockford and Chicago metro areas. In the Rockford area, a mobile home had a large tree fall on it, unfortunately causing one fatality.


A third round of severe thunderstorms developed during the evening of August 11th and lasted into the overnight hours. While these thunderstorms were not as widespread as the previous two rounds were, they still produced multiple instances of tree damage with the most concentrated area of damage occurring in Kankakee County.

Severe Weather Reports from August 9 to August 11, 2021
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Additional recaps can be found on the NWS Chicago Past Events Page
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