More Rain, Snow, and Windy Conditions Pushing Across Western U.S.

The West Coast will remain stuck in a loop of storm after storm after storm heading into the weekend. The region has continued to be the target of the Pacific storm train, delivering loads of rain, mountain snow, and gusty winds to the Northwest and Northern California in recent weeks. More of the same is in store in the days ahead. Read on for all of the details.

Late Week Storm Targeting the Northwest and Northern California

Foresters are warning that the Pacific Northwest and Northern California will be under the threat of flooding, mudslides, and avalanches as another round of storms takes aim at the western U.S. The forecast models are calling for at least two more major storms to push into Washington, Oregon, and Northern California over the next few days. Each storm will compound the threat of flooding and other hazardous impacts.

It has already been a wet end to December with several inches of rain falling along the coastal areas and up into the west-facing mountainsides. The large waves and rough surf conditions have created beach erosion and overwash to areas as far south as Central California this week.

The latest storm moved ashore late Thursday in the Northwest. Widespread rainfall accumulations of 4 to 8 inches are on tap for the heaviest hit areas along the coast. The busy Interstate 5 corridor that connects Seattle with Portland is forecast to see 1 to 2 inches of rain out of this late week system.

For instance, Seattle will pick up about a quarter of an inch of rain during the day Friday with another quarter of an inch expected overnight. The moisture will lighten up in the Emerald City on Saturday, however, the second storm will send the heavy rain fall on Sunday once again. Seattle is anticipating moderate temperatures with highs in the upper 40s and low 50s during this time period. Overnight readings will slip just a few degrees from the high temperatures.

You will find a similar story down the road in Portland. The Rose City will see the heaviest rain ignite late Saturday with a half of an inch in the forecast. This persistent rain will linger through Sunday with another quarter of an inch expected to add to the running total.

Heading up to the high country, snowfall accumulation will land between 6 and 12 inches near pass level. The highest terrains of the Cascades above pass level can expect snowfall measurements of 1 to 2 feet.

The low-lying elevations of Northern California will miss out on the heaviest of the rain with this system. This part of the region is expecting light to moderate rainfall.

Donner Pass on Interstate 80 in California will likely see enough snow to slow travel at times on Friday. Be sure to check the hourly forecast if your plans call for travel over this heavily trafficked mountain pass in the Sierra Nevada.

The highest wind speeds will whip up across the coastal region of southwestern Oregon and into Northern California. Widespread gusts of 40 to 60 mph are in the forecast as the storm moves farther inland on Friday. Some gusts could hit speeds of near 80 mph during the worst of the storm's wrath. High winds will also be an issue to the east of the Sierra Nevada and Cascade ranges at the beginning of the storm's journey.

Details of Second Storm

The second storm will train over Northern California and southern Oregon. This is when forecasters have pinpointed the highest risk of a brief atmospheric river to come to life.

You can expect rainfall amounts of 4 to 8 inches from the coastal areas stretching to the east to the lower terrains of the Siskiyous. This rain will stick around through the latter part of the day Sunday.

Moving to the north into Washington, rainfall of 1 to 4 inches is on the horizon for the end of the weekend. Rainfall of this magnitude is enough to send the weather flowing out of some of the short-run streams originating in the Coast Ranges, the Olympics, the northern Sierra Nevada, and the Cascades. Meteorologists are also cautioning that urban flooding is a likelihood for the Interstate 5 corridor through the end of the weekend.

The weekend storm will result in higher snow levels in the Sierra Nevada when compared to the Friday storm. The difference in the snow levels will raise the threat of avalanche danger as the snow becomes more unstable.

The Washington Cascades will dodge the worst of the snow associated with the weekend storm. However, the Oregon Cascades will once again be in the bullseye with 6 to 12 inches of snow expected for the top elevations.

High Winds Among Many Hazards of the Incoming Storm Train

The most powerful winds coming along with the weekend storm will ignite on the back end of the weather maker. The stiff westerly winds will support the development of large swells for the coast of Oregon and to the south into Northern California.

The ground is becoming more saturated across much of the Northwest and Northern California. This saturation will make it more vulnerable to rockslides, mudslides, and washouts as the moisture machine continues to hammer the region. The high winds associated with these storms will also make the trees more susceptible to falling over in the loose ground.

Compounding the hazards will be the forecast of low-elevation rain showers and snow for the higher terrains in between the two main storms. While there will be some stretches of dry weather, it will be a soggy end to the year for this corner of the country.

One again, Southern California will escape the wrath of the Pacific storm train. Cities such as Los Angeles will enjoy dry conditions with highs hovering in the mid to upper 60s throughout the weekend. The mercury will be on the upswing by the start of the new week with a high of 75 degrees in the forecast for the first day of 2025.

The forecast is looking more favorable for those tired of the precipitation. New Year's Eve and New Year's Day are both shaping up to be mostly dry for the Northwest and Northern California. The exception will be across the northern half of Washington where a storm on the horizon for British Columbia, Canada could creep to the south. This system could bring more rain and high winds for parts of the Washington coastline by the middle of next week.

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