• Series of atmospheric rivers to bring heavy rain to Washington, Oregon, and northern California through early October

    ByRishav Kothari

    A series of atmospheric rivers (AR) is forecast to hit the U.S. West Coast from late September through early October, beginning with a strong AR that made landfall over British Columbia on September 26, 2025. Forecasts show moderate AR conditions in Washington, Oregon, and northern California on September 28, followed by a stronger system making landfall on September 30 and potentially continuing into October 7.

  • U.S. West flood risk increases sharply with wet soils during atmospheric river storms

    ByReet Kaur

    Wet antecedent soil moisture increased streamflow magnitudes by 2–4.5 times during atmospheric river storms across 122 U.S. West Coast watersheds between 1980 and 2023, according to a new analysis. The study, published in the Journal of Hydrometeorology on June 4, 2025, establishes a nonlinear threshold effect in soil moisture, above which flood response to atmospheric rivers increases sharply.

  • Major atmospheric river (AR) event possible over the U.S. West Coast next week

    ByTeo Blašković

    U.S. weather models, including NCEP and GEFS, project an over 80% chance of a strong atmospheric river making landfall in northern and central California from April 1 to 2, 2025, with additional outlooks from the NWS Climate Prediction Center (CPC) indicating wetter-than-normal conditions and a moderate risk of heavy rain and mountain snow between March 31 and April 4.