Atmospheric River Forecast Map Shows Heavy Snow, Rain for West Coast State

Meteorologists are warning that the first atmospheric river of the fall and winter season will bring heavy rain to the western half of Washington and snow to higher elevation areas in the state this weekend.
Last winter, the West Coast faced a slew of atmospheric rivers that caused devastating floods and landslides. Meteorologists are again predicting a wet winter for the West Coast, according to an AccuWeather forecast published Monday. The storms will begin increasing in November and December for Northern California and the Pacific Northwest, with atmospheric rivers shifting south to Southern California in January before likely returning to Northern California for the remainder of the winter.
Atmospheric rivers are a “long, narrow region in the atmosphere—like rivers in the sky—that transport most of the water vapor outside of the tropics,” according to the National Oceanic and Atmospheric Administration.
In Washington, the weekend’s atmospheric river will bring widespread heavy rain and some heavy snow, according to an AccuWeather report published Thursday.
“A plume of moisture will extend from well out over the Pacific Ocean and be directed at southern British Columbia and the northwestern corner of Washington,” AccuWeather Senior Meteorologist Brett Anderson said in the report. “It will behave like a giant firehose or atmospheric river.”
Anderson went on to say that up to 8 inches of rain was forecast to fall on the western slopes of the Olympic Mountains in northwestern Washington. There could be locally higher rainfall amounts. Snow is primarily expected to fall in British Columbia, Canada, with up to 4 feet forecast for Vancouver, but higher elevation terrain in Washington could also see some snow.
AccuWeather Senior Meteorologist Scott Homan told Newsweek that some of Washington’s highest elevations, such as areas up to 10,000 feet, could see 8 inches of snow, but heavy snow isn’t posing a threat to more populated areas of the state. Smaller amounts of snow, up to 3 inches, are forecast for areas around 3,000 feet in elevation.
Homan added that atmospheric rivers aren’t abnormal for this time of year.
“We have lots of cooler air moving in and more active weather for the West as we head into the wintertime,” he said.
The winter-like storm comes as several other states are under a winter storm warning that could bring up to 22 inches of snow to high-elevation areas in Utah. Montana and Colorado also are forecast to get snow this weekend. Frost advisories and freeze warnings are in place for the Midwestern and Eastern U.S.