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.
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.
Three atmospheric rivers (ARs) are forecast to impact the Pacific Northwest (PNW) from Wednesday, March 19, 2025, into early next week, bringing significant precipitation and potential excessive rainfall to Oregon and Washington.
Two atmospheric rivers (ARs) along with a low-pressure system are forecast to bring significant precipitation to much of the U.S. West Coast from March 8 to 14, 2025.
