As temperatures approach triple digits in western WA on Sunday and exceed that in eastern WA through Tuesday, we're also looking at some smoke impacts in places. And possibly some ozone in two known hotspots.
Local fires
The Mosier fire in Wasco County, Oregon is currently sending light smoke into south central WA and causing some Moderate air. As surface winds turn offshore tomorrow, assuming the fire continues to puff, we could see some smoke drift along the gorge toward Portland/ Vancouver and cause air to degrade to Moderate. The current smoke forecast model is a bit pessimistic for Saturday. No reason to suspect that most of eastern WA will see Moderate air tomorrow. It should be mostly restricted to the gorge and the south central Cascades. Other fires in north central WA could cause occasional Moderate conditions elsewhere.
Here's the most likely smoke forecast for the whole weekend.
More distant fires
Upper level flow turns south by Sunday and models are suggesting some smoke from norther California fires could be transported over western WA by then. Not expecting much of it to mix down to the lowlands, but those views of Mt Rainier might not be that clear, and sunsets might be a bit more resplendent.
Siberian smoke hanging around the Gulf of Alaska is mostly expected to get shunted to our north. Not much of it is mixing down to the surface anyway.
Ozone
Cascade foothills in eastern King and Pierce counties, and also the Tri Cities could see ozone levels (loosely called "smog") creeping up over the weekend. More info on ozone pollution here.
And finally, here's an exciting new data tool
EPA has partnered with the US Forest service to make available data collected nationwide (mostly by citizen scientists) using PurpleAir sensors. These sensors are known as "low cost sensors" for a reason, and they are not able to match the data quality and accuracy of permanent sensors. So while they often help fill data voids, there are a lot of caveats with their use.
EPA & USFS worked with states around the country to develop conversion factors to transform PurpleAir data to better match up against permanent monitors in near-real-time. Corrected data are now available alongside the rest of the fine particle pollution (PM2.5) data. PurpleAir monitors are shown as squares. Here's a snapshot of the short explanation on the page.
