Portland woke up under a gray, murky blanket Tuesday, with patchy to at times dense fog cutting visibility in river valleys and low-lying routes and slowing down the morning drive. Temperatures are starting in the upper 30s to low 40s, with dew points nearly matching the air temperature, which means the air feels cool but relatively comfortable for most people. By late morning, sunshine should chew through the low clouds, and highs are expected to climb to around 60°F in the city.
Foggy Mornings, Sunny Afternoons
The fog is expected to thin and lift through the mid-to-late morning as skies clear and a ridge of high pressure settles over the region. That setup favors mostly dry, mild days through Friday, even if mornings stay a bit gloomy. For more on how this air pattern can lock pollution in place and affect air quality, check out our earlier air stagnation advisory coverage.
Gorge Gusts and Air Stagnation
While much of the metro stays calm, the Columbia River Gorge is gearing up for a wind show. Easterly gap winds are expected to strengthen on Wednesday and Thursday, with parts of the far eastern metro looking at gusts over 35 mph and exposed ridgetops possibly topping 50 mph.
Away from the Gorge, though, it is a different story. Light winds and shallow mixing will keep air from turning over much, setting up stagnant conditions in interior valleys. The National Weather Service has an Air Stagnation Advisory in effect through Friday and notes that this pattern can trap pollutants near the surface and help fog redevelop in the mornings. Ensemble guidance also points to a shift back to cooler, wetter weather late this weekend, with rain chances climbing from Saturday afternoon into Sunday. For the latest timing and totals, keep an eye on updates from the National Weather Service.
What To Expect For Your Commute
If you are heading out early, budget extra time and be ready for visibility to change fast on bridges and surface streets. Even after a bright midday, fog can sneak back into river corridors later on.
Out on the water, boaters should know offshore seas are running at Small Craft Advisory levels this morning, and beachgoers should stay wary of sneaker-wave risk through much of the week. Anyone with asthma or other respiratory issues may want to take it easy on heavy outdoor exertion while the air stagnation advisory remains in place.
