Western WA still seeing high temperatures, some smoke despite looming autumn

The Puget Sound region is wrapping up quite the warm stretch, likely the last warm spell of the season. High temperatures in Western Washington reached the 80s and even the 90s in some cities, including on the Pacific coastline.

A lot of temperature records in Western Washington were broken Thursday. At Seattle-Tacoma International Airport (Sea-Tac Airport), it hit 90 degrees. That broke the record of 88 that was set back in 1973. Olympia soared to 95 degrees. The old record, also established in 1973,  was 91.

The North Coast city of Forks hit 96 degrees Thursday, shattering the previous record of 87 set in 2014. Hoquiam, which reached 89 degrees, tied their record set in 1955.

More MyNorthwest weather: Surge of hot summer weather to come before autumn equinox

Looking at Friday, the coast was expected to see a lot of cooling. That area is going to get down into the 70s, maybe 80 degrees. That’s substantially cooler than Thursday.

The interior part of the state will see a small amount of cooling, just a few degrees here and there. But, for instance, after hitting 95 Thursday, Olympia will get to 94 Friday.

However, it will eventually clear out as the area gets more ocean air coming in over the weekend. That will cause temperatures to fall into the 70s by early next week.

In addition, there is some wildfire smoke coming up from Oregon. It’s high altitude. There won’t be impact around Seattle but the area probably is going to see moderate air quality in the Puget Sound region through much of Friday and into Saturday. Airnow.gov reported that as of 5:30 p.m. Friday the AQI was at 66 in Seattle, which is in the yellow or “moderate” level of concern category. It gets back to green or “good” when the AQI falls below 70.

The AQI is expected to stay in the low 60s into the weekend.

What is causing this late warm patch

Driving this late summer warm spell is building high pressure aloft over the Pacific Northwest combined with low-level flow turning offshore from the interior to the Pacific Ocean. This weather pattern often creates unseasonably warm temperatures. The average high temperatures for the interior of Western Washington in early September are in the lower to mid-70s.

Despite the soggy latter part of August, much of Western Washington is well behind the average annual rainfall to date. Some locations are as much as four inches below average and much of the interior is considered to be in abnormally dry or moderate drought conditions, according to the latest drought monitor.

So this late summer surge of above-average temperatures will also heighten the threat of wildfires. With conditions remaining this dry, any fire has the potential to become quite active and spread.

Help prevent any local wildfires by avoiding tossing burning materials out of vehicles, tightening tow chains to avoid dragging on the pavement and continuing to postpone outdoor burning. Many counties have outdoor bans in place through the end of this month.

Looking more at the weekend weather

For those planning to attend the Seattle Seahawks season opener on Sunday, it looks like an ideal day for football with plenty of sunshine and temperatures warming into the mid and upper 70s during the afternoon.

More on the Seattle Seahawks: The telling signs to focus on in Seahawks’ season opener

Looking ahead, no significant rainfall is anticipated with more summer-like and close to average temperatures heading into next week. Yet, longer-range guidance is pointing toward cooler and wetter conditions once the calendar approaches the following weekend.

So enjoy this late summer warm, dry weather. Fall is just around the corner.

Editors’ note: This story originally was published Wednesday, Sept. 4, 2024. It has been updated and republished multiple times since then.

Contributing: Steve Coogan, MyNorthwest

Ted Buehner is the KIRO Newsradio meteorologist. You can read more of Ted’s stories here and follow him on X.