A Coastal Flood Warning remains in effect for the San Diego and Orange County coasts through October 29, 2026, as high tides and elevated water levels threaten roads and low-lying property. The National Weather Service (NWS) also has Coastal Flood Advisories for other shoreline areas, including Los Angeles-area beaches, San Francisco Bay, Monterey Bay and Humboldt Bay.
An early-season atmospheric river associated with a potent upper-level closed low is forecast to bring 25–75 mm (1–3 inches) of precipitation to parts of the western United States through 05:00 PT (12:00 UTC) on September 5, 2026. The Weather Prediction Center (WPC) placed interior northern California, eastern Oregon, and western Idaho under a Marginal Risk of excessive rainfall for September 3–4, while Marie-related moisture raised a separate, more uncertain California rainfall risk later in the forecast period.
A large marine heatwave has persisted along the U.S. West Coast since summer 2025, raising sea surface temperatures about 1.7–2.2°C (3–4°F) above average across parts of the Northeast Pacific. In a report published March 3, 2026, the National Oceanic and Atmospheric Administration (NOAA) Fisheries said this is only the third time in the observational record for the California Current ecosystem that such a large portion of coastal waters has remained anomalously warm for so long into winter without El Niño conditions.
Three atmospheric rivers are expected to impact California between December 20 and 25, 2025, producing 250–500 mm (10–20 inches) of rain over the Sierra Nevada and 75–180 mm (3–7 inches) over southern coastal ranges. The strongest system is forecast to peak on December 23–25 with IVT values surpassing 750 kg m⁻¹ s⁻¹ and AR3–AR4 intensity.
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.
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.
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.
Four back-to-back atmospheric rivers are forecast to make landfall along the U.S. West Coast between November 3 and November 9, 2025. Heavy rainfall totals of 76–130 mm (3–5 inches), with isolated amounts up to 177 mm (7 inches), could lead to localized flooding in parts of northern California and Washington State throughout the week.
