August 29, 2018

The Smoke Outlook for the Next Week

Air quality today is far better over the region today that last week, but some smoke is present and will stay present.

Here is the latest surface particulate map from the wonderful  Washington State smoke website :  Most of the sites are green (good air quality)....but there are problem spots.   Because of the Maple Fire on the Olympic Peninsula and persistent wildfires on northern Vancouver Island, some smoke is getting into western Washington.  That is why a few central Puget Sound sites are reporting moderate levels (but on the low level of moderate).  And the persistent fires on the northeast slopes of the Cascades are producing moderate to unhealthy values there.

This pattern is going to stay in place for the next week, based on on the latest model runs.  Forecasts are for the maintenance of a ridge of high pressure offshore and generally northwesterly flow--no heat wave--but the Vancouver Island smoke can waft into western Washington.  To illustrate, here is the forecast map for upper level (500 hPa) flow at 5 PM Saturday.  No heat wave.  Generally onshore flow.

The entrance of clouds into our region has revealed a problem with the NOAA/NWS HRRR smoke model I have shown in previous blogs.   It bases its fire location on satellite data (like VIRS) and when clouds occur, the fires are not well defined.  The Canadian smoke model seems to do better.

I suspect that we have seen the worst of the smoke for this season here in western Washington, so it is useful to view a trace of air quality at Seattle to get some perspective (see below for June 28th through today).   Particulate levels (PM2.5) were relatively low through approximately August 10th (although there was a small spike on July 4th).    We had two weeks of smoke, with some peaking into the very unhealthy range (above roughly 120).  Now we have settled down into low-moderate level (roughly 15-20)-- some smoke, but far down from the previous peaks.

It is interesting to compare this against recent years.   For 2017, there was a two week period in early August, that was bad, but not quite as bad as this year.

And 2015, a much warmer year that this one-- a summer similar to what we expect during the 2070s, had far less smoke that this year.

Clearly, there are subtleties to the connection between smoke and weather, something I will explore in a future blog.

Finally, for those living in Seattle, a new smoke measurement site has been put on top of my building at the UW, thanks to the US Forest Service (and particularly thanks to Susan O'Neil of the FS that supervised its installation).  This link will get you there (see graph at 8 AM Wednesday below)


  1. Cliff, I'm curious if you have an opinion on the efficacy/accuracy of "consumer grade" air quality monitors. I've noticed that air quality monitors outside of the Seattle area are quite sparse (only 1 on the eastside) and that even within Seattle the readings can vary quite a bit; I was wondering if they would be useful tools for folks further away from monitoring stations.

    (e.g. IQAir AirVisual Pro; I won't be offended if you censor the name if you don't want product names referenced in your blog comments)

  2. Cliff - will this new UW monitoring site be listed on, or just the forest service site?

  3. RE air quality monitors: I've been finding the website to be a good source of particulate air quality information. At least here in the Methow valley there are many more air monitors. As of today (8/30/18) there are 21 monitors compared to 2 state monitors (Winthrop and Twisp). The sensors are laser based and seem to track well with the data from the official state monitors. We've been impressed enough to buy our own ($230+shipping and tax) and will soon be providing data to the purpleair web site.
    Here is one review:

  4. At what point do we begin to sound the drought alarm bells? Our vegetation in Seattle is rapidly dying, trees are increasingly distressed everywhere you look, and the outlook for any measurable rain disapates just as soon as it may appear in a forecast. It was forecasted to rain today ... then tonight ... then early morning hours. Now, nothing.

    Yes, our summers are dry, but this one is worse than any I have seen. For the majority of Seattle, July and August brought us, now, virtually no rain. I have a terrible suspicion that September will bring much of the same. At what point do we declare this a bonafide drought? I am very troubled.

  5. Cliff -- During our smoky conditions of late, can one escape the smoke by hiking (or driving) high? Many local hikes ascend to the tops of mountains whose altitudes are above 5000 ft. Is that high enough to be above the smoke? Are there maps or websites that provide answers to altitude-related questions such as this? Thanks.

  6. Been raining steady all morning at the Admiralty inlet. Weather forecast says 0% chance of precipitation!!!

    Yet another for casting failure.

    Seem like you weather folks perfer to predict the weather for 100 years from now instead of for the next day.

    Frustrated, as a farmer I rely on knowing when crop destroying rains are coming.

    Rain= a loss of money. Especially when forcasts are wrong.

  7. Drought? No unusual drought at the Admiralty inlet. Had 1 inch downpour a couple weeks ago, and several trace rains since. Heck still have Mosquitos!

  8. Eric, your memory appears to be severely impaired, because for the past six summers some folks have been making the same observations about the PNW. However, in all of those years the rains eventually came back in full force in the Fall and Winter months. BTW, since when is September a month for any appreciable precipitation? Maybe we're due for a genuine drought year, but this kind of hand wringing doesn't help the discussion.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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