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Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

Overview

A powerful upper-level disturbance moving through the Rockies and Plains on June 6, 2020 sparked the development of a line of thunderstorms that brought widespread damaging winds from Utah and Colorado through northeastern Wyoming, western South Dakota, and southwestern North Dakota. Given the scope and intensity of the damaging winds, the storm system was classified as a "derecho" by the Storm Prediction Center.

Derechos are characterized by a several hundred mile-long swath of persistent severe wind gusts (58 mph or greater), with embedded wind gusts that are considered significantly severe (75 mph or greater). There is more information about derechos here.

This derecho rocked our county warning area during the afternoon and evening of June 6th, leading to over 100 reports of wind gusts of at least 58 mph and multiple reports of 80 to 95 mph winds. This derecho caused widespread damage, with 60 to 90+ mph winds reported. Sections of I-90 needed to be closed for a time due to construction site damage and vehicle rollovers.

The derecho also produced at least two brief tornadoes. One was west of  Billsburg, SD, in Haakon County. The other did damage to the Badlands/White River KOA campground southeast of Interior in Jackson County.

The CIMMS Satellite Blog has additional details about this event:

https://cimss.ssec.wisc.edu/satellite-blog/archives/37107

North of Belle Fourche, SD Courtesy Conquer The Storm
North of Belle Fourche, SD
Courtesy Conquer The Storm

Most Significant (75+ MPH) Wind Gusts in a Day Since 2004

The Storm Prediction Center created a graphic with the most significant wind gusts in a day since 2004. June 6, 2020 is #1 with 44 reports.

Derecho Track

Courtesy Storm Prediction Center

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