Overview
- The National Weather Service has a dense fog advisory in effect until Wednesday noon for the Portland metro and the broader Willamette Valley, with visibility dropping to a quarter mile or less.
- Additional fog advisories cover coastal areas and other valleys, including the Oregon Lower Treasure Valley through late Wednesday morning, creating hazardous travel and possible slick spots from freezing fog.
- Air stagnation advisories remain in place from Tuesday morning through Friday morning across the Eastern Columbia River Gorge, north-central Oregon and central Oregon.
- A separate stagnation advisory spans large parts of the Willamette Valley and Portland-area highlands through early Friday, with forecasters warning of deteriorating air quality.
- Oregon DEQ has extended an air quality advisory for Lake and southern Klamath counties and for southern Deschutes County through 10 a.m. Friday, urging no outdoor burning, limiting wood stove use, and precautions for vulnerable groups such as staying indoors with HEPA filtration.