Oregon – Still air hangs heavy over the Willamette Valley this morning, softening city lights and holding cold close to the ground. Frost sparkles on rooftops while a faint haze lingers near road level, signaling a winter pattern that refuses to move.
The National Weather Service has issued an Air Stagnation Advisory for the central and southern Willamette Valley, including Portland, Eugene, Salem, and surrounding communities. The advisory remains in effect until 4 p.m. Wednesday, as light winds and limited air movement allow pollutants to build near the surface.
Temperatures sit well below normal early today, dipping into the upper 20s in Eugene and the lower to mid-30s around Portland. Patchy frost and areas of freezing fog develop during the morning hours, especially in low-lying neighborhoods and along river corridors. Drivers should watch for slick spots on bridges and ramps along I-5, I-84, and Highway 99. Conditions may improve by late morning, but refreezing remains possible after sunset.
Air quality concerns grow quietly during these stagnant setups. Smoke, vehicle exhaust, and fine particles become trapped under the inversion. People with asthma, heart disease, or other respiratory conditions are urged to limit outdoor activity. State agencies recommend avoiding outdoor burning and minimizing wood stove use, even if the air looks clear.
By afternoon, sunshine helps temperatures rebound into the upper 40s to near 50. To be fair, the warmth feels welcome, but it does little to break the inversion. Frost and fog redevelop tonight, repeating the cycle Tuesday and Wednesday mornings.
Looking ahead, long-range outlooks suggest precipitation chances rise later next week as colder air spreads east and warmer air builds across the Southwest.
How does the air feel where you live this morning? Share what you’re seeing as winter tightens its grip across Oregon.
Five-Day Weather Outlook (Portland–Eugene Corridor)
Today: Frost early, sunny, highs near 49–50
Tuesday: Morning frost and fog, mostly sunny, highs near 49–51
Wednesday: Frost early, increasing clouds, highs near 48–49
Thursday: Patchy frost, partly sunny, highs near 47–48
Friday: Morning frost, partly sunny, highs near 46–48
