West Coast Storms could bring flooding, first snow

On January 31, 2025By Littum

Several rounds of heavy rain and snow will target the west coast over the next week.
Some floods are possible from Oregon to North -California.
Several meters of snow is possible from the cascades to Sierra Nevada.
Some rainfall could reach southern California.

A significant, long -term pattern change is about to bring several days of rain and possibly lower chopping snow to the northwest, including the first snow of the season for Seattle and Portland.

Currently, Winter Storm -watches and warnings are limited to the higher heights of Cascades and Rockies, but these alarms are likely to expand to lower heights through the weekend when cooler air arrives. Winter Storm warnings are issued in places where travel can become difficult to impossible and power cuts may occur.

(Winter Weather Alerts issued by National Weather Service.)

H erere a look at both systems:

System # 1: Friday-Saturday

The first system arrives at Pacific Northwest late Friday until early Saturday with a plume of warmer, Pacific Air.

Here’s a look at the moisture’s plume, known as “Pineapple Express” because of its connection to Hawaii:

Current precipitated water

(Deeper atmospheric moisture in this image is shown by plums of yellow, orange and red contours. Clouds appear by different shades of white.)

This primarily brings rain to the Interstate 5 corridor, including Seattle, Portland and Sacramento.

Snow falls first to higher heights before falling to some care levels, including Snoqualmie Pass, Friday. There may be intermittent periods of rainfall in the warmer afternoon hours at pass level. Gusty relationship could also accompany snowfall.

(More: For even more granular weather data tracking in your area, see your 15-minute detailed details of our Premium Pro -experience.)

The worst of this first system will affect the West to Saturday and then tense something. There will probably not be a pure break in rain or snow between the two systems in all places.

There may be some spotted flooding along the Pacific coast from western Washington south to the Bay area and at the foot of Sierra Nevada. A couple of communities between Santa Rosa, California and Gold Beach, Oregon, and at the foot of Sierra could see more than 5 inches of rain.

Up to 3 feet of snow can fall into the higher heights of the cascades and northern Sierra. Lighter snowfall is collected down to as low as 2,000 feet.

Rain and snow forecast

(This should be interpreted as a wide view of where the heaviest rain and snow can fall. Higher or lower amounts may occur.)

System # 2: Through next week

At late Sunday or Monday, a few low -pressure systems will again increase rainfall for the coming week. A northern system off the coast of Washington brings colder air and fetches another system that comes from Hawaii with ample moisture.

The resulting system can swirl through the region into the midweek.

Snow levels appear to be significantly lower with this system than the first. Some low villages including Seattle, Portland, Boise, Idaho and Medford, Oregon, should see lighter snow during this period. These snowfall plots are likely to be on the lighter side, but any snow would be the first of the season for Seattle and Portland.

(More: Further beef up your forecast with our detailed, Time-for-Times collapse in the next 8 days-only available on our Premium Pro -experience.)

More feet of snow are probably throughout the cascades and Sierra and also in the northern rockies, but it is too early to say how much snow falls.

Floods and landslides could become a problem for northern California because of the prolonged nature of this weather pattern.

Tuesday’s forecast

(While it is too early to find out who is expected to see gossip or freezing rain (ice cream).)

By Tuesday or Wednesday, at least some rainfall could make it as far south as the Los Angeles Metro area. This may offer temporary relief from the threat of fires, but will not turn off the drought over southern California.

Jonathan Belles has been a graphics meteorologist and author of Weather.com For 8 years and also helps with the production of videos for the Weather Channel an Español. His favorite weather is tropical weather, but also enjoys covering weather and news stories with high influence and news and winter storms. He is a two-time candidate from Florida State University and a proud candidate from Skt. Petersburg College.