US Weather Update: Multi-Day Winter Storm to Snarl Travel in Pacific Northwest with Heavy Rain, Mountain Snow [NWS]

A multi-day winter storm is expected to snarl travel in the Pacific Northwest region of the United States with heavy rain and mountain snow.

This is according to the National Weather Service (NWS), which described the weather system as a "long-duration storm" that will impact the region through the upcoming weekend. Even the coastal areas and lower elevations of the Cascade Mountains in the region can also experience moderate to heavy rain, as well as periods of heavy snowfall.

Earlier this week, the weather service issued a winter storm warning for the region, as well as a similar winter storm alert last week. As December has finally arrived, winter weather conditions are lingering in different parts of the country, especially in the northern tier of the US.

In recent days, the Northeast was also subjected to a lake effect snow and winter weather alerts affected tens of millions of Americans nationwide.

Multi-Day Winter Storm

In its short-range forecast on Friday, December 1, the NWS' Weather Prediction Center (WPC) at 2:47 a.m. EST (local time) stated that the multi-day winter storm is expected to cause travel disruption across the Northwest, where a winter weather advisory is in place for parts of Washington, Montana, and Idaho. The forecast is valid until Sunday, December 3, meaning that wintry conditions are possible in the said states throughout the weekend.

The NWS explains that the meteorological winter is on a fast start across the Northwest, Great Basin, and Rockies since an abundant moisture will flow inland from the Pacific Ocean at least in the next few days.

In addition, the main weather hazards for the Pacific Northwest will be heavy mountain snow and heavy rain. A strong atmospheric river is also expected to envelop the region on Sunday, following snowy, rainy precipitation on Friday and Saturday, December 2.

Winter Weather Impacts

The long-duration winter storm, accompanied by the lingering atmospheric river, over the Northwest and its surrounding regions may result in flooding due to heavy rain and thick snowfall accumulations. These hazards can create dangerous driving conditions. Flight disruption such as delays and cancellations due to reduced visibility from snow is also expected.

In its winter storm warning for the region recently, the US weather agency warned the public to reconsider delaying unnecessary travel if possible. As the multi-day winter storm can intensify this weekend, the agency recommends that individuals should take precautions and bring extra food, water, flashlights, and other essential items should an emergency occur.

During the North American winter storm in December 2022, a winter storm combined with a cold wave killed at least 100 people across the Pacific Northwest, including in Oregon, Washington, and the Canadian province of British Columbia. Related winter weather events last year also caused flooding and mudslides amid an atmospheric river, according to local authorities during that time.