Portland, OR – Oregon is expected to face a prolonged period of flooding risk, heavy precipitation, high winds and significant mountain snowfall from December 20 into early January, according to an updated outlook from the NOAA Climate Prediction Center.
Forecasters say multiple atmospheric rivers will begin pushing into the Pacific Northwest around December 20, directing steady moisture into western Oregon. With soils already saturated from recent storms in neighboring Washington, NOAA expects flooding to expand into Oregon by mid-next week, persisting into late December at minimum.
A moderate risk (40–60%) of heavy precipitation is posted for much of western Oregon from December 20–26, extending from the coastal counties to the Cascades. NOAA also highlights a moderate risk of heavy snow for the Cascades and Sierra Nevada during the same period, signaling treacherous travel over mountain passes.
Enhanced onshore flow will also drive periods of strong winds along the coast, interior valleys and higher elevations. Gusts could become hazardous at times, especially during the strongest moisture surges.
Forecasters emphasize that saturated soils and repeated rainfall will keep landslide vulnerability elevated, particularly along steep terrain in western and southwestern Oregon. Rivers, creeks and low-lying urban areas may also experience rising water levels as the pattern continues.
Above-normal precipitation chances extend into early January, as La Niña-driven systems remain active across the region. NOAA says the storm track is likely to continue funneling moisture into Oregon through at least the first full week of 2026.
Residents are encouraged to monitor local National Weather Service offices for flood watches, wind advisories and winter storm warnings as the pattern evolves.
