Particle.news
Download on the App Store
3 ARTICLES
·
last wk.

Late-October Atmospheric River to Soak Pacific Northwest With Heavy Rain, Mountain Snow and High Winds

CPC highlights the greatest risk late next week for northern California and southern Oregon, with flooding and travel disruptions possible.

SANTA BARBARA, CALIFORNIA - FEBRUARY 04: A person walks through flood waters as a powerful long-duration atmospheric river storm, the second in less than a week, impacts California on February 4, 2024 in Santa Barbara, California. The storm is delivering potential for widespread flooding, landslides and power outages while dropping heavy rain and snow across the region. (Photo by Mario Tama/Getty Images)
Image
An Atmospheric river moving over the U.S. Pacific Northwest as of 00:30 UTC on October 18, 2025. Credit: GOES-19, RAMMB/CIRA, The Watchers

Overview

  • NOAA and NWS say a true atmospheric river is likely to arrive late next week, with guidance focusing on October 24–27 and CPC outlooks extending impacts through October 25–31.
  • Forecasters expect widespread heavy precipitation from northern California through Oregon and Washington, with heavy mountain snow in the Sierra Nevada, Cascades and parts of the northern Rockies.
  • CPC’s Probabilistic Hazards Outlook flags a high risk of heavy precipitation October 25–26 in northern and central California and southern Oregon, with moderate risk extending north through October 28.
  • Flood potential is elevated for western Washington, Oregon and northwestern California, and coastal and high terrain areas may see hazardous winds, with gusts locally exceeding about 37 mph.
  • Models also suggest the moisture plume could progress across the central U.S. toward the Great Lakes around October 27, indicating a possible late-October storm for Michigan that remains uncertain.