Seattle, WA – A classic early December storm pattern is setting up across the Pacific Northwest, with long-range forecasts calling for repeated rounds of heavy rain, gusty winds, and significant mountain snow as November transitions into the new month.
According to NOAA’s Climate Prediction Center, temperatures from Nov. 29 through Dec. 5 are expected to run near to slightly below normal across Washington, Oregon, Idaho, and western Montana. While coastal areas will remain relatively mild, colder air funneling into the interior will support increasing chances for snow in higher terrain.
The precipitation outlook shows a high-confidence zone of above-normal precipitation centered directly over the Pacific Northwest. This signals an active storm track off the Pacific, capable of delivering multiple systems that bring heavy rain to lowlands and accumulating snow to mountain ranges.
The Cascades, Olympics, Wallowas, Bitterroots, and northern Sierra foothills could all see significant snowfall, especially at elevations above 3,500–4,000 feet. Passes such as Snoqualmie, Stevens, Santiam, and Lookout Pass may encounter slick, snowy conditions, with reduced visibility during heavier bursts.
Major metro areas including Seattle, Portland, Spokane, Boise, Eugene, and Yakima should expect steady rain, periodic downpours, and occasional gusty winds depending on storm strength. Localized flooding, urban ponding, and river rises are possible in western Washington and northwestern Oregon, where soils remain saturated from recent rainfall.
Forecasters note that this is not one storm, but rather a multi-system pattern typical of early winter. Travel impacts could accumulate over time, especially for mountain commuters and holiday travelers navigating I-5, I-84, and U.S. 2.
Residents across the Pacific Northwest should stay alert to daily forecast updates as early December brings one of the wettest patterns of the season so far.
