Massive La Nina precipitation coming to the Northwest

By Cliff Mass Blog • December 3, 2025 1:30 am
Cliff Radcliffe Expect stormy weather in the coming week. A perch surf fisherman tries his luck along the Pacific Ocean at Ocean Shores this past week.
Cliff Radcliffe Expect stormy weather in the coming week. A perch surf fisherman tries his luck along the Pacific Ocean at Ocean Shores this past week.

Heavy rain and snow? Check.

Skiing before the holidays? Check.

Bring reservoirs to near normal levels? Check.

Threaten flooding on some local rivers? Check and check again!

The next few weeks are going to be an exciting meteorological ride, so buckle up.

A series of atmospheric rivers will make landfall over our region, resulting in bountiful precipitation, including snow in the mountains.

The next week will include three atmospheric rivers:

A modest atmospheric river on Thursday,

A strong one next Monday.

And a Godzilla atmospheric river next Wednesday. Directed right towards us.

Precipitation totals over our region?

Through Friday morning, a good wetting, with the mountains soaked by 3-5 inches. Just the start.

By Sunday morning, very large precipitation totals will have accumulated in the mountains, with some locations receiving 5-7 inches.

But then the third, crazy-strong atmospheric river hits, and by next Friday, the totals become insane, 10 inches and more in much of the mountain areas.

The European Center modeling system is doing the same thing, which gives us confidence that a major event is ahead. Mountains will be hit very hard.

By a week from Friday, the rivers will rise rapidly, some to flood stage. Consider the situation for the Snoqualmie River near Carnation. The first two atmospheric rivers will bring the level up to flood stage. The third, stronger river will cause substantial flooding.

Snow in the mountains? Huge amounts will fall. Yards of snow in some locations. The ski season will begin. Our water resources will be greatly enhanced. Winter recreation will beckon.

Cliff Mass is an American professor of atmospheric sciences at the University of Washington, specializing in numerical weather modeling, regional climate prediction and the weather of the Pacific Northwest. He is a well-known meteorologist who is influential in Seattle due to his popular blog, frequent media appearances, and his book, The Weather of the Pacific Northwest. Mass is also a fellow of the American Meteorological Society and has a public profile that sometimes sparks controversy.