National Weather Service United States Department of Commerce

Heavy Rainfall to Bring Flooding Threat to California; Heavy Snow in the Sierra

A strong atmospheric river will bring heavy rainfall to California through the holiday week. The heaviest rainfall is expected on Wednesday in the Los Angeles Basin. Flash and urban flooding is possible. A prolonged heavy snowfall is expected in the Sierra Nevada from the atmospheric river, raising concerns for major snow‐load impacts. Travel may be difficult to impossible over the passes. Read More >

Overview

A long tracked severe mesoscale convective complex (MCS) moved out of eastern Nebraska and South Dakota into central and western Minnesota, including west-central and northwest Minnesota, on May 12, 2022. This MCS was particularly long lived and intense producing numerous 80+ mph wind gusts and several tornadoes. This event met the classification of derecho. Other notables include the thick dust that accompanied gusty winds, heavy rainfall, as well as strong 60+ mph non-thunderstorm wind gusts on May 13 associated with the strong low pressure within North Dakota.

As of June 30, 2022, the May 12, 2022, Midwest Derecho event holds the highest number of significant wind gust (75+ mph) reports from any one convective complex on record with 68 reports of measured wind gusts 75 mph or greater. The previous record for the highest number of measured, significant wind gusts was 64 reports during the Central Plains-Midwest derecho of December 15, 2021.