Oregon – Headlights glow dimly through thick gray air across the Portland metro this morning as dense fog settles into neighborhoods, river valleys, and low-lying roads. The air feels heavy and still, a classic winter inversion locking in both fog and pollution.
According to the National Weather Service in Portland, a Dense Fog Advisory remains in effect through midday, while an Air Stagnation Advisory continues through early Friday morning. Visibility has dropped to a quarter mile or less in parts of the Willamette Valley, Inner Portland Metro, and North Clark County lowlands. Calm winds and cold overnight temperatures are allowing fog to linger longer than usual.
Drivers along I-5, I-205, Highway 26, and surface streets near the Columbia and Willamette rivers should expect sudden visibility changes. Wet pavement and reduced sightlines increase the risk of rear-end collisions during the morning commute. Slow down, use low-beam headlights, and allow extra stopping distance.
Air quality is also deteriorating as pollutants remain trapped near the ground. People with asthma, heart disease, or other respiratory conditions may notice irritation or breathing difficulty. Outdoor burning is discouraged, and limiting prolonged outdoor activity is advised.
Fog gradually thins later today as sunshine breaks through, with afternoon highs climbing into the low 50s. Clear nights follow, allowing patchy fog to redevelop each morning through the end of the workweek. Despite sunshine, the stagnant pattern holds until stronger winds arrive late week.
Winter hazards in western Oregon are not always dramatic. Sometimes they creep in quietly, slowing travel and affecting health. Are you seeing dense fog or hazy skies where you live this morning?
Five-Day Outlook for Portland, OR
• Today: Patchy dense fog early, then mostly sunny. High near 51.
• Thursday: Mostly sunny. High near 56.
• Friday: Sunny. High near 54.
• Saturday: Sunny. High near 54.
• Sunday: Mostly sunny. High near 53.
