CW3E AR Update: 24 October 2025 Outlook

October 24, 2025

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Pair of Atmospheric Rivers to Bring Precipitation to the Pacific Northwest and Northern California

Two atmospheric rivers are forecast to make landfall over the Pacific Northwest and Northern California over the next week, bringing precipitation to the Pacific Northwest and Northern California.
The first AR made landfall over the Pacific Northwest this morning (Fri 24 Oct) and is forecast to propagate down the coast through Sun 26 Oct. A secondary low is forecast to develop behind the AR later today and bring additional moisture to the PNW coast tomorrow, Sat 25 Oct.
The EPS is forecasting stronger IVT over the PNW coast with both the initial AR and secondary low. The EPS is forecasting AR3 and AR1 (according the Ralph et al. 2019 AR Scale) conditions in Northern Oregon with the AR and secondary low respectively, whereas the GEFS is forecasting AR2 and AR0 conditions for the same period.
The NWS Weather Prediction Center (WPC) 72-hour precipitation totals by 5 AM PT 27 Oct are forecast to be ~3-5 inches over the Washington, Oregon and Northern CA coasts as well as over the Cascades associated with the first AR and secondary low.
The WPC issued marginal risk (level 1 of 4; ≥5% probability of flooding) excessive rainfall outlooks (ERO) for western Washington and Oregon, northwestern California, and the Northern Sierra foothills for 5 AM PT Fri 24 Oct through Sun 26 Oct.
There is model-to-model uncertainty regarding the strength of the second AR and associated surface low as well as the time of landfall. While both EPS and GEFS members contain significant uncertainty in the timing and intensity of the AR, ~65% of members in each ensemble are forecasting AR conditions over the Northern Oregon coast late on Tue 28 Oct.
Precipitation is forecast to forecast to fall mostly over the Pacific Northwest with the second AR, with the WPC forecasting the highest precipitation totals (1–2 in.) over Washington and portions of Northern Oregon.
The GEFS and ECMWF ensembles are in good agreement regarding the potential for a significant AR event in the Pacific Northwest late next week. This is an unusually strong signal given the long lead time (~8 days).