PORTLAND, Ore. (KOIN) — The wildfire smoke will continue to linger over the Portland metro, Salem and Eugene for Thursday, but then the chance for severe thunderstorms brings flash flooding concerns.

The Air Quality Alert was extended for some parts of Oregon until noon Friday. There are weather changes on Thursday evening as an upper-low gradually moves in to the region.

Wildfire Reports

Current Air Quality Index

Weather Alerts

Thursday afternoon, the thunderstorm chances increase near Eugene. Elsewhere, showers will arrive by Thursday night, but the severe thunderstorms will arrive a little later and into Friday.

These thunderstorms may include damaging hail and winds, along with heavy downpours.

Flash flooding will be a major concern for the Cascade foothills, which have seen wildfires for more than a week. The threat continues into Friday, although it’s less severe. However, the Willamette Valley will be in for scattered heavy downpours through the end of Friday.

The extended forecast calls for more showers, cool temperatures, and a chance for thunderstorms by Thursday. Smoke should thin with improving air quality this weekend. But it’s possible the smoke may return at times, even next week, as large fires continue to burn.

Thunderstorm potential, September 17, 2020 (KOIN)