Key Messages from the NOAA Climate Prediction Center
Issued December 9, 2025 and Updated December 12, 2025
Atmospheric Rivers, Flooding, and High Winds in the Pacific Northwest and California
A mid-level ridge over the Bering Sea and a downstream trough in the northeastern Pacific increase the likelihood that atmospheric river events will continue affecting the Pacific Northwest and expand southward to central California by December 20, and to southern California by December 22.
Given the significant river flooding already impacting western Washington and northwestern Oregon, it seems likely that elevated rivers and saturated soils will linger into late December at least. This will increase the risk of flooding with any additional heavy precipitation later in the wet season. Landslide vulnerability will remain elevated.
(a) The flooding risk is expected to persist into at least late December after expanding into Oregon and northern California by the middle of next week.
(a) A moderate risk (40-60%) of heavy precipitation is indicated by the Week-2 U.S. Hazards Outlook and is posted from most of western Washington through west-central California for December 20-26. Another moderate risk for heavy precipitation is posted from west-central California southward to the Mexican border, for December 22-26.
(a) A moderate risk (40-60%) for heavy snow is designated for the Cascades and most of the Sierra Nevada, December 20-26.
(a) Enhanced onshore flow supports a moderate risk (40-60%) of high winds for much of the West Coast and northern Interior West, with the highest gusts expected along the coast and at higher elevations.
(b) During a wet time of year, there is more than a 60 percent chance of above-normal precipitation from northern and central California into southeastern Oregon and northern Nevada. Odds exceed 50 percent from northern and central Oregon into southern California.
(c) The La Niņa pattern with periods of enhanced onshore flow is favored to persist into the New Year.