Two successive atmospheric river pulses are affecting the Pacific Northwest this week, delivering multi-day heavy rainfall and flooding risk across western Washington and northwestern Oregon. The first made landfall early December 9, and a stronger second pulse is forecast to arrive late December 9–early December 10, maintaining high integrated vapor transport and major flood potential through December 11.
Flood watches and warnings were issued across western Oregon and Washington on December 7, 2025, valid through December 12, as strong atmospheric river produces sustained rainfall, rising river levels and increasing landslide risk.
A major atmospheric river (AR4–AR5 possible) is forecast to make landfall over the Pacific Northwest early Monday, December 8, 2025, and persist through Wednesday, December 10, bringing multiple days of heavy rain and elevated snow levels. Ensemble guidance shows ~70–80% of members reaching at least AR4 in southern coastal Washington, with ~20–30% indicating AR5, raising the risk of widespread riverine flooding.
Three atmospheric rivers (ARs) are forecast to make landfall over the Pacific Northwest (PNW) through December 10, 2025, producing prolonged precipitation and high moisture transport across western Washington and Oregon.
Two weak atmospheric rivers (ARs) are forecast to make landfall over Washington and Oregon between November 25 and 27, 2025, bringing 50–100 mm (2–4 inches) of rain to coastal and mountain areas.
A mid-level trough deepening along the US West Coast is forecast to evolve into a cutoff low over Southern California and a potential atmospheric river (AR) over the Pacific Northwest between November 19 and 24, 2025.
Heavy rain caused by an atmospheric river hit parts of the Bay of Plenty on November 18, 2025, with MetService reporting localized downpours of 25–40 mm (0.8 to 1.6 inches) per hour and an Orange heavy-rain warning in effect
At least 6 fatalities have been reported as of Sunday, November 16, 2025, as a powerful atmospheric river continues to impact California. With heavy rainfall of up to 200 mm (8 inches) being forecast, authorities are preparing for the threat of flash floods, landslides, debris flows across the state.
Evacuation warnings were issued across multiple burn-scar zones in California on November 13, 2025, as a strong atmospheric river delivered high rainfall rates and elevated debris-flow potential.
A strong atmospheric river is forecast to move onshore across California through Saturday, November 15, 2025, bringing heavy rain, strong southwest winds, and elevated flash-flood risk across northern, central, and southern parts of the state.
