Seattle, Washington – A weak atmospheric river is expected to bring moderate to locally heavy rainfall to the Pacific Northwest this weekend, increasing the risk of isolated flooding and hazardous travel conditions.
According to the U.S. National Weather Service, moisture associated with the system will move onshore Saturday and persist through Sunday, producing widespread rain across western Washington and Oregon. Forecast rainfall totals of 2 to 5 inches are possible near coastal and urban corridors, with locally higher amounts along windward terrain.
In the Seattle metro area, rainfall is expected to intensify along major travel routes including Interstate 5, Interstate 405, and State Route 99, where ponding on roadways and reduced visibility may develop during heavier rain periods. Similar impacts are expected along I-5 from Portland through Eugene and Medford, where totals could reach 3 to 6 inches by Sunday night.
The National Weather Service also reports that higher elevations of the Cascade Range are likely to see accumulating snowfall, particularly near Snoqualmie Pass along I-90 and Willamette Pass near Highway 58. Snowfall totals will depend on elevation, with the greatest impacts expected above pass level.
While widespread river flooding is not currently forecast, isolated flooding in low-lying and poor drainage areas remains possible, especially where heavier rain bands stall. Urban areas, small streams, and recent burn scars are most vulnerable.
Residents, commuters, and weekend travelers are urged to monitor road conditions, avoid driving through flooded roadways, and stay updated with local NWS alerts. Outdoor recreation in the Cascades may be impacted by rapidly changing weather conditions.
The National Weather Service advises checking the latest forecasts and statements at weather.gov, as rainfall and snowfall amounts may be refined as the system evolves.
