National Weather Service United States Department of Commerce

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Overview

In the afternoon of August 8th, 2020, thunderstorms developed across eastern Wyoming and western South Dakota. These brought large hail and damaging winds to the area through the evening. One storm that developed over the Black Hills produced grapefruit-sized (4.5 inch) hail! As the storms shifted eastward, they formed a line, developing into a mesoscale convective system as more storms converged together. The main threat changed from hail to strong winds, with nearly 80 mph gusts reported across south central South Dakota. As the storms passed, magnificent mammatus was seen by many.  Image
Pactola (R. Strom)
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