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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 strong upper-level low pressure moved from the Rockies on May 5, 2024, to the northern plains on May 6-8, 2024. Deep surface low pressure developed over southwestern North Dakota. Ahead of the system, strong gusty southeast winds developed on May 5 pulling in plentiful moisture. As the system strengthened May 6-7, strong northwest winds (up to 79 MPH) developed with heavy, wet snow over the highest Black Hills. Numerous power outages were reported coincident with the snow and high winds.

As the two air masses clashed, a line of thunderstorms developed on May 6 in the morning. The thunderstorms produced minor flooding in Gillette, WY. Over western South Dakota, a line of thunderstorms developed – containing isolated severe thunderstorms – with one storm producing two tornadoes near Mud Butte, SD early in the afternoon on May 6.

Significant liquid-equivalent precipitation fell. 1 to locally 3” fell over northeastern Wyoming and the Black Hills. Amounts on the western South Dakota plains varied widely with some folks getting very little and others around an inch. 14-18” of snow fell near Four Corners, WY, and O’Neil Pass, SD.

Deep snowcover on a ranch with a barn in the back
Moskee, WY
Courtesy Becky Stoddard
Flooded intersection with stoplights
Gillette, WY
Courtesy David King
Deep snowcover on a ranch with a barn in the back
Near Mud Butte, SD
May 6, 2024 1245 PM MDT
Courtesy Joshua Tatman
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