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Western U.S. Braces For Active Weather Week

October 19, 2021
UPDATED By WeatherBug Meteorologists
A slow-moving storm system will deliver more valley rain and elevation snow to parts of the Western U.S. through midweek. A couple more moisture-laden Pacific disturbances will arrive mid-to-late week as well.

The storm system will jump onto the eastern Colorado Plains early today before accelerating into the far northwestern corner of Iowa by Wednesday morning. Given its bounty of Pacific moisture and cold air aloft, the inconspicuous system will leave behind plowable snow in Utah’s Wasatch Range, a large part of Wyoming, and even into the east-central Plains.

Meanwhile, the lower valley floors will rake in one-half to an inch or locally higher totals through early Wednesday morning. Unfortunately, it won’t make much of a dent in the short or long-term drought that continues to affect the Western U.S.

Winter Storm Warnings and Winter Weather Advisories remain in place through midweek from Utah’s northern Wasatch Range to far western South Dakota. The heaviest snowfall accumulation will occur at 8,000 feet and above, where 8 to 14 inches will blanket the ground. Lower Plains elevations in Wyoming and South Dakota’s Black Hills will start as rain before switching over to a heavy, wet snow. This will limit totals to 2 to 5 inches.

The combo of heavy snow and occasional gusts near 40 mph will create difficult travel, especially at pass level along Interstates 80, 84, and 25. Interstate 90 west of Rapid City, S.D., will become slippery overnight on Tuesday as well.

Before the first system departs the Western U.S., a new one will march onshore later today. It will lose its tenacity quickly on Wednesday, gaining little inland traction beyond northern California to the Northwest’ Interstate 5 corridor.

The storm will be most notable for gusty winds, peaking at 40 to 60 mph, especially along Oregon’s coast including Port Orford and Gold Beach. These gusts could down trees, causing power disruptions. Travel will be difficult, especially for high-profile vehicles. Already, High Wind Watches and Wind Advisories are in place across northern California and southern Oregon.

One-half inch to locally 2 inches of rainfall is forecast along the coast and valleys with 3 to 6 inches of snowfall above 4,500 feet in California’s northern Trinity County. A Winter Weather Advisory is in place for northern Trinity County, Calif.

Even after the midweek storm, rain and mountain snow will continue straight through the weekend as the active weather pattern continues. Impressive rainfall totals ranging from 2 to 4 inches are expected through Friday from northern California to western Washington with several more inches possible by the end of the upcoming weekend.

The precipitation will be a welcoming sight for the parched Western U.S. which has been battling a devastating drought. However, too much precipitation coming at once could elevate the flood risk, especially later this week as soils saturate with the upcoming heavy rain.