Very Unhealthy Air Quality Persists, Gradual Relief Coming

Very unhealthy air quality continues to impact the Puget Sound region. The smoke is less dense than yesterday, but it is still thick enough to keep temperatures in the 60s and limit the sun's rays.

"Relief" is going to be gradual. Smoke will lessen through Monday as stronger onshore winds aloft push it out. However, in the lower areas in elevation (Puget Sound Lowlands), relatively stagnant air will keep air quality elevated through at least Wednesday. 

Here is Puyallup's air quality (AQI) reading at 6 PM Sunday. Wow. 260 is the worst we have seen so far. It is in the middle of the "very unhealthy" category. As they say...it gets worse before it gets better.

You can refer back to my "Understanding Air Quality" blog post for definitions of the AQI categories.

Below is the AQI forecast from the Puget Sound Clean Air Agency via the EPA AirNow app. This particular forecast applies to Pierce and South King Counties, but similar numbers/trends will be found across the Puget Sound area.

When I talked about relief being "gradual"...this is what I'm referring to. Even if smoke has lessened, air quality will take more time to improve due to relatively stagnant air and little precipitation.

Let's take a look at the near surface smoke forecast from the HRRR Smoke model. 

Here is 6 PM Sunday.

You'll notice that smoke is still quite thick across the Puget Sound area (verified by a look out the window), with improvement across the coast. 

Here's 11 PM Sunday.

Major improvement over Western Washington. Still noticeably smoky though. 

Here's 11 AM Monday.

Smoke continues to improve across Western Washington. We won't notice improvement as fast as we think, because the smoke will stick around in lower elevation areas longer than at higher elevations (notice the clear area over the Olympic Mountains).

Finally, here's 11 PM Monday.

Noticeable surface smoke keeps moving in off the coast through the day. It will be better, but not great, especially since we're in the Lowlands. This trend matches up with the air quality forecasts I mentioned earlier.  

Regarding smoke relief, here's the bottom line: Noticeable smoke will stick around through at least Monday night. While much better than Sunday, air quality will stay degraded and will be slow to improve, possibly taking over 3 days.

Now let's look at rain forecasts. We will be using the UW WRF model.

Below is rain through 5 AM Monday. Nothing over Puget Sound, but some rain on the coast. 

Here's something to know...when rain looks like "lines" of more rain around areas with less, like in this image, that means the rain is likely to be more of the showery variety, with some cells producing more rain than others.

Back to the forecasts. Here is rain from 5 AM Monday-5 AM Tuesday. Rain reaches Puget Sound by Monday night.

Notice that rain is of the showery variety. Your location will determine your rain. Also remember that these forecasts aren't perfect, and the location of rain could (and will likely) move by a few miles. This isn't much rain, but enough that you'll notice.

Finally, here is precipitation from 5 AM Monday to 5 AM Wednesday. 

There's a decent rain shadow on the NE side of the Olympics. Most of the area has received 0.05-0.16 inches of rain. 

Now for some real good news...here is forecast precipitation through the next 7 days.

Our area gets 0.5-2.5 inches of rain!!! The Oregon Cascades get at least 0.3 inches, and parts of NE WA get up to 2.5 inches! The most rain is likely past Wednesday. This will help to banish the smoke and give firefighters a big hand with fighting these fires. Hopefully they'll get a real handle on them! 

Each day from Tuesday through at least Friday has a chance of rain. Every time it rains, it will improve the air quality and get rid of more smoke. 

In short...the smoke situation will begin to improve, and rain is on the way.