CW3E AR Update: 22 October 2025 Outlook

October 22, 2025

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Atmospheric Rivers Forecast to Bring Precipitation to the Pacific Northwest and Northern California

A strong atmospheric river (AR) is forecast to move over the Pacific Northwest late Thu 23 Oct/early Fri 24 Oct and shift southward along the coast into Northern California through early Sun 26 Oct.
A mesoscale frontal wave is forecast to develop within the first AR, resulting in the development of a secondary low pressure region and notable dual peak in the maximum IVT forecast for coastal points in the Pacific Northwest.
A second weak, zonally oriented AR is forecast to move onshore over Oregon and Northern California on Sun 26 Oct, resulting in AR conditions over this region through early in the day on Mon 27 Oct.
CW3E’s AR Landfall tool is highlighting the potential for additional AR activity next week, beginning after 1 Nov.
Roughly 82% of GEFS and ECMWF ensemble members are forecasting an AR 3 or greater (based on the Ralph et al. 2019 AR Scale) for a point along the southern coast of Oregon, with 16% forecasting AR 4 conditions. There is still significant uncertainty as to the AR Scale forecast associated with the second AR at this time.
The NWS Weather Prediction Center (WPC) is forecasting a broad region of 2–4 in. of rain over coastal Washington, Oregon, and Northern California with the highest totals >5 in. forecast over the Olympic Peninsula, the Cascades, and coastal terrain in Oregon and Northern California.
Freezing levels are forecast to begin relatively high with this event resulting in primarily rainfall over terrain initially, but falling freezing levels later in the event may lead to significant snowfall along high elevation, particularly in the Cascades.
The NWS WPC has issued marginal risk (at least 5%) excessive rainfall outlooks highlighting the potential for high-impact rain in coastal Washington, Oregon, and Northern California for 5 AM Fri 24 Oct–5 AM Sun 26 Oct.
NWS Weather Forecast Offices have begun messaging the potential hazard associated with the first AR, namely the coastal beach hazards, high winds forecasts, possibility for heavy rainfall, and significant high elevation snow.