Oregon temperatures to spike toward 100, raising wildfire danger and air quality concern

Willamette Valley temperatures will rocket toward record levels Thursday and Friday while wildfire danger ramps up and air quality could degrade.

The National Weather Service issued an excessive heat warning from noon Thursday to 10 p.m. on Friday as temperatures rise toward 100 both days in Portland, Salem and Eugene.

The hot and dry weather will bring increased fire danger and east winds will likely to cause wildfires to grow and bring smoke into western Oregon.

The type of extreme wildfires that took place in September of 2020 and 2022 are not currently forecast.

Willamette Valley will get very hot, but not quite a September record

Temperatures over 100 in September are very rare in the Willamette Valley, as the average high is around 80 degrees in Salem, Portland and Eugene.

“I don’t think we’re going to break the September record, but it’s still a very rare event,” NWS meteorologist Miles Higa said. “We’ll be nearly 20 degrees warmer than normal.”

The last time Salem, Portland and Eugene hit 100 degrees in September was Sept. 2, 1988. That record-setting day brought temperatures of 104 to Salem, 103 in Eugene and 105 in Portland.

However, Hillsboro did reach 100 degrees on Sept. 2, 2017, NWS records said. That was the same day the Eagle Creek Fire ignited in the Columbia River Gorge.

The Willamette Valley has never had back-to-back 100 degree days in September.

“It’s the class setup for a heat wave on the West Coast — a big ridge (blocking ocean air) that causes a warmer air mass to be trapped and heat up,” Higa said.

Community organizations are bracing for the heat wave. ARCHES Project has outreach teams in Salem distributing water and other cooling supplies. The teams will also be directing people to cooling locations, like the day center or local libraries. The ARCHES Day Center at 615 Commercial St. NE extended its hours until 7 p.m. to capture the hottest part of the day.

During inclement weather, libraries can serve as vital spots to cool off and hydrate. The Salem Public Library is open downtown until 6 p.m. Thursday and until 5 p.m. Friday. Due to budget restrictions, the downtown location and West Salem branch reduced hours this year. The West Salem branch will not be open until Saturday at noon.

Oregon wildfire danger increases

The hot and dry air, combined with some east winds, is likely to bring increased wildfire danger to the Cascade Mountains, Higa said.

New wildfires sparked and brought multiple evacuations east of the Cascades mainly over Labor Day weekend. There are still active wildfires burning on the west side of the state, but many have a high level of containment.

“I think we’ll see an increase in fire activity where it’s currently burning, and definitely be a concern for a few days,” Higa said. But he added that the severity of the winds is not expected to reach 2020 or 2022 levels.

The east winds are expected to cause the fires in eastern Oregon to grow and send smoke over to western Oregon, which could degrade air quality on Thursday and Friday.

More moderate temperatures and even some precipitation are expected to return next week, Higa said.

“It should start to feel a lot more like fall next week,” he said.

Zach Urness has been an outdoors reporter in Oregon for 16 years and is host of the Explore Oregon Podcast . Urness is the author of “ Best Hikes with Kids: Oregon ” and “ Hiking Southern Oregon .” He can be reached at zurness@StatesmanJournal.com or (503) 399-6801. Find him on X at @ZachsORoutdoors.

This article originally appeared on Salem Statesman Journal: Oregon temperatures to spike toward 100, raising wildfire danger and air quality concern