East winds expected in Oregon this week less severe than 2020 event

PORTLAND, Ore. (KOIN) — Oregon's easterly wind threat is increasingly more likely as the summer heat builds Thursday.

An unusually late summer spike in heat will align with potentially gusty easterly winds Thursday. It's the easterly winds, downsloping over the Cascades, that will dry conditions rapidly from the Columbia River Gorge to the Portland, Vancouver metro area.

A downslope wind event is when air moves up and over the Cascades. As the air descends into lower elevations it warms up, speeds up, and dries out. That's the perfect combination for wildfires to start and spread rapidly.

The Labor Day wildfires that started in 2020 in western Oregon started and spread rapidly during an east wind event. Thankfully, this year's drought is considerably less to 2020's severe and extreme drought conditions. Despite a few days of excessively hot and dry conditions this summer, Oregon has had a few cool and damp days to lessen the blow of an east wind event.

Although the NWS has issued warnings for rising temperatures and an increased wildfire risk, KOIN 6 Meteorologist Kelley Bayern said wind conditions are significantly less severe than in 2020.

“The 2020 Labor Day fires were made worse by a historic east wind event, where winds gusted up to 40-50 mph around the west Columbia Gorge and east Portland metro area,” Bayern said.

Easterly winds will likely return for a brief amount of time Friday. That's when temperatures will warm to nearly 100-degrees again. Some locations may struggle to get as hot as forecasts show due to easterly winds blowing smoke into parts of the Willamette Valley. Air quality will likely be impacted later this week, but could also prevent temperatures from warming as hot as predicted.

An onshore flow or westerly winds will help cool western Oregon and southwest Washington by the weekend. Near normal conditions are expected to return early next week with a slim chance for rain.