Monday, September 14, 2020

Much More Pessimistic Air Quality Outlook and Model Problems

Things are looking far more pessimistic this morning, with considerably less improvement in western WA and OR air quality than expected yesterday.

And these problems are highlighting issues with our modeling systems and ability to observe/simulation smoke in the lower atmosphere.   Paradoxically, such problems are what modelers like me live for, providing opportunities to learn and improve our systems.

Air quality has not improved overnight, as shown by the summary at 4 AM this morning from the excellent Washington State Dept of Ecology WASMOKE site.  Hazardous air over Puget Sound, the Willamette Valley, and parts of Eastern WA.


The model forecasts yesterday (HRRRSMOKE, Washington State University's AIRPACT SYSTEM, the USDA Forecast Service GRAYSKY) were suggesting improvement by now....and it is not happening.   Even the experts at WA Department of Ecology were going for better conditions by this time.  

But surface air quality remains poor and at the very least is not improving as fast as the models suggested.   Last night I was worried about the forecast and couldn't sleep well--and now that I see what is going on, I am going to give up on my pillow.    

I suspect I understand some of the problems and what they imply for the forecast.    But before I explain, let me note that forecasting smoke is very new technology and very difficult for several reasons.  And the current situation plays to several of our weaknesses.

Problem 1:   A cool, stable layer of smoke near the surface.

Air quality has improved greatly above roughly 5000 ft, as strong southwesterly winds have developed aloft.   Below that level, cold, smoky air is trapped by an inversion, a layer of the atmosphere in which temperature warms with height.   Think of the inversion as a barrier to atmospheric motions, a cap to the vertical movement of air.  It prevents the smoke from mixing out vertically. 

This situation is shown clearly by a plot of the balloon-launched radiosonde sounding at Forks, on the WA coast (see below).

Temperature is shown by the right-most solid line, dew point temperature by the left line. Height is in terms of pressure, with 700 being roughly 10,000 ft.  Wind are shown by the vectors/pennants to right (more little line, the stronger the wind).  

There is a cool, moist layer below roughly 5000 ft in which the winds are weak.  About roughly 5000 ft (840 to 820 in terms of pressure in hPa), you can see the inversion, above which the winds are much stronger and from the southwest.


The trouble is that the models are not accurately portraying the lower dead-air layer, bringing too strong winds below the inversion and mixing out the smoke more than reality.  Unfortunately, a classic problem with our forecast models, which we are struggling to fix.

And it is worse than that.  The smoke itself is strengthening the inversion by preventing solar radiation (and thus warming) from penetrating to the surface and by warming of the upper smoke layer by the sun.  Details we have to get right.

Just to impress you with the strength of the inversion, Sunday afternoon temperature were in the mid-50s in Portland, while in the mid-70s around Mt. Hood (see below, click to enlarge).


Problem 2:  Smoke over the Pacific

We are now getting onshore flow aloft (and to a lesser degree at the surface) and we are pulling smoke that was ejected during the past few days over the Pacific.  2-5 days ago, a huge amount was injected offshore (see image for Sept 11 below), and now some of that smoke is being pushed back in, and the models have an uncertain handle on its distribution.


The outlook this week

This week is good illustration why we need humans watching the automated systems.   It like a plane on autopilot that is about to crash into the mountain--we need to take over the controls.

The latest HRRRsmoke forecast is still improving the air quality too rapidly, particularly over western Washington and the coast (see forecast below for 3 PM).


Reality is shown by the plot of small particles at Beacon Hill in Seattle over the past 48h.  We are probably past the worst smoke concentrations and air quality is very slowly improving.  That is probably the story for the rest of today.  Slow improvement.  And it appears that this will be the story for Tuesday as well.  I just checked the latest National Weather Service forecast discussion--they appear to have the same take on the situation.  Sorry.


One Encouraging Note

Let me end with a positive.  Although air quality is not improving quickly, the decline in smoke above us yesterday  is resulting in more sunlight.  Below is the solar radiation at the UW for the past three days (Friday to Sunday).  Friday had some smoke, but solar radiation was not abysmally low (15.49).  The bottom dropped out on Saturday (4.28), worse than most dark, winter days.  But Sunday was a bit bitter (8.86) and hopefully it brightened your spirits.

_____________________

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42 comments:

  1. So much for your "Benign Wildfire Year" from here: https://cliffmass.blogspot.com/2020/08/benign-wildfire-year-in-washington-state.html

    The HRRR models STILL haven't adjusted for the lack of clearing wind as of the 11Z run.

    We're in this smoldering garbage for at least another few days to a week.

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    1. It was benign for the most part. I thought we'd gotten away with a nice summer. Then, BOOM! At least we're close enough to the rainy season that it can only last so long :(

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    2. It was very benign compared to many other years. Remember that more than one arsonist was caught setting multiple fires, as well as the ones started on accident like with the gender reveal parties. It still could have been quite benign if those fires hadn't been set.

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  2. Thanks, Cliff. I am now a contributor.

    Corvallis OR

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  3. Edit? Sunday was much BETTER. love your work

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  4. Thanks for clearing up why the smoke forecast was wrong everyday. Makes it tough to plan for the health of workers schedules. Glad I erred on the safe side. And Glad you are there to push the leading edge further out on the science of forecasting weather and smoke! Also- you might have meant “brighter” on Sunday rather than “bitter”? “Bitter” was accurate as to my frustration with the smoke though...Thanks for having our backs!

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  5. Hi Cliff, thanks for the update. Interested to learn your thoughts on the European Opernicus model that is available via the Windy app? This model for PM2.5. was showing the slow improvement yesterday and is consistent today with smoke returning mid week and not clearing until late Thursday afternoon.
    https://www.windy.com/-PM2-5-pm2p5?cams,pm2p5,2020091520,47.093,-121.652,7

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  6. This is some depressing reading combined with NWS Seattle's update. At least my home prison will be a little brighter today. sigh

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  7. Sunday was more than a bit bitter, but I think you meant "a bit brighter"?

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  8. This is like some horror movie.

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  9. Thanks for the explanation of the modeling difficulties. Fortunately we have not had many events like this to correct our models.

    As a curiosity, the surface winds on CalTopo appear to be non-directive, or going in the opposite direction of the winds discussed in the post. I assume these winds are just indications of the inversion not producing mixing at the surface, or am I missing something?

    https://caltopo.com/map.html#ll=47.0776,-122.32178&z=7&b=goes_0&o=mbt&n=0.1&a=modis_mp%2Cwxd_wspd-01

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  10. Thank you for this and all these explanations! Very helpful.

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  11. Is part of the problem that the models do not take into account the cooler temperatures? Without the predicted warming, there is less instability than the models predict to get the air moving. This reminders me of the big ice storm we had years ago where the models were days off in the duration.

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  12. I truly appreciate your public service in communicating to all of us. Your explanations, while not cause for too much optimism today, give me a factual understanding of what is happening. Many thanks for your blog and podcast!

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  13. This entire nightmare has been unprecedented in myriad ways, but the most fascinating aspect to me is just how much this smoke has suppressed our surface temperatures. Truly, this is analogous to a “nuclear winter” type scenario. Smoke absorbs infrared light, so even though we’ve basically been under clear skies all week/weekend long, the solar energy is being sucked up by the smoke layer overhead and largely never reaches the surface, as Dr. Mass pointed out. By that same token, water vapor doesn’t absorb infrared anywhere near as efficiently as smoke does, which is why a layer of clouds, even a thin one, can trap in radiational cooling overnight and keep the surface temperature up. However, the smoke overhead is also absorbing the radiated heat at night, so surface temperatures keep cooling overnight, limited only by the dewpoint in a completely saturated atmosphere, hence the persistent fog. It’s hard to tell what’s fog and what’s smoke anymore, and sadly this has become a self-reinforcing cycle.

    As a result, surface temperatures have been tanking for the last 4-5 days. Starting Thursday going through yesterday (Sunday), here’s a comparative of previously forecast highs -vs.- our actual “nuclear winter” reality, - (and the disparity therein.) This is for down here in PDX metro (actual temps are from my station in Milwaukie)

    Thu 9/10 - 96 - 72 - (–24)
    Fri 9/11 - 94 - 68 - (–26)
    Sat 9/12 - 87 - 64 - (–23)
    Sun 9/13 - 85 - 61 - (–24)

    The toll this has taken on my garden is, well, tragic. In just 4 days, everything has pretty much self-terminated. My corn stopped taking up water, and though it was basically time to harvest anyway, the stalks have suddenly shriveled and turned brown. My tomatoes, instead of ripening, have turned a ghastly reddish grey/white, and the plants themselves are dying. My summer squash seems to be handling this alright, it’s sending out a ton more blooms, though I’m afraid that might be a desperate dying gasp, as many of the large leaves have suddenly wilted away. Same with my beans, which ordinarily would keep producing into November, but despite a new flush of blossoms, the leaves are now looking quite dead.

    It will be really interesting to survey and document the damage done by all this once the smoke has cleared and our atmosphere goes back to relative climatological normal. In the meantime, all I can do is sit inside and watch the world outside my windows wither and die.

    But hey, on a positive note, at least the air is no longer p!$$-yellow! And on another positive note, at lease this suffocating death cloud isn’t radioactive!

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  14. https://earth.nullschool.net/ has more conservative forecast - shows gradual clearing over the next 6 days.

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  15. Thank you! Now I understand our zero wind situation here in Yakima. It is very strange not to have our usual happy breezes. I’m guessing that since we are further east, we’ll have these conditions around longer. Sigh.

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  16. Thank you, Cliff for the daily postings during this extraordinary time.

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  17. I understand the talk about solar radiation, but what about the low pressure system off the coast that's drawing south winds from the smoke areas right into the puget sound area?

    It seems like that's a big contributing factor in the amount of smoke we'll have the rest of this week and doesn't seem to be talked about. I noticed this yesterday morning by watching the NAM and GFS models for the low pressure system off the coast. It looked fairly certain/clear to me that the winds would create more smoke, not less, even if the upper layer blows off due to high elevation winds. Low elevation winds are still from the south thanks to the storm.

    I'm in the lea hill area (475ft, east auburn) and we saw our AQI decline rapidly exactly in the time the local forecasts were saying we should be seeing improvements. We've gone from 190 AQI over the weekend, then hit 260 sunday morning, then 340+ sunday night, now back to 260 AQI today and I expect it'll jump again later today.

    We saw the sun yesterday morning for the first time in 3 days (well, just a small glowing dot behind the smoke), today the sun is gone again.


    I feel like too much emphasis is being put on the upper winds and not enough on what the actual low elevation winds are doing and the direction they are coming from.

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  18. Tell us again how climate change is no big deal

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  19. I am from Portland and it is nasty outside. We have had daily air values around 500 for the past several days. What I do find interesting and had no idea would happen it how all this smoke is greatly effecting the weather. Kind of like how the winter inversion keeps the sun from burning it off with the low sun angle. Of course with smoke you cant burn it off. I think it will take a decent weather system to come in to clear the majority of this smoke out.

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  20. As someone who was a kid in LA in the 1970s, this has been all too familiar. So an inversion layer doesn't surprise me at all. You might want to at least give AQMD a call, and see if they want to collaborate.

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  21. Look up the firefighting teams about DEWs. (Deep Energy Weapons). It makes sense when you compare it with what's happening.

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  22. You posted a couple years ago about the early autumn pea soup fog and how hard it is to predict. This looks very similar.

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  23. Well...I woke up this pm, with a slight coughing fit, despite all windows being closed...first time for that!...but I must cruise for my espresso coffee anyway...I checked that AirNow chart....the reading here in Everett is 30 points higher than yesterday!..Very Unhealthy!...Paranoia is seeping into my oxygen-starved brain!...Hope the coffee pulls me out of this mindset!...and no mention today, about that that anticipated rain that was gonna help clean out our area!

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  24. I really appreciate your explanation of the difficulty of modeling smoke. I'd like to know if this same thick marine (low fog) layer would be here the last few days without the smoke, or has the smoke influenced our current weather. And in this thick mixed smog, how much is smoke and how much us fog?

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  25. The BOW, WA Weather Reporting Rock-On-A-String is wet at 5:15 pm Monday.

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  26. Cliff, is it possible that the offshore smoke lowered ocean temps enough to quash the front?

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  27. I'm already starting to feel the effects of this pollution. I'm an otherwise healthy person, I run a lot and I'm starting to feel issues breathing.

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    1. It is amazing, to see quite a few folks in my Everett neighborhood, doing yardwork, letting their kids run around outside...usually not wearing a mask...oh well, this is Trump Country, so I guess all this smoke is Fake Smoke!

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  28. It's really ugly all right. I think that perhaps the biggest factor in the increase of fires is that our summers are no longer punctuated by occasional periods of rain lasting 2 to 5 days as they were, as I remember, in the 1970's and 1980's. Used to be that the third weekend of August could be counted on for it. A topic for a future blog?

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  29. Air quality in SW Washington is still declining. Were in the hazardous range 357 and still rising Cliff. I mean so far off it is ridiculous. Simply observing the SURFACE FOG LAYER FORMING EACH EVENING...man... Use your eyes, depend less upon models for short term trends.

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  30. How do these models compare to atmospheric dispersion models like NARAC used for chemical/radiological dispersion?

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  31. Cliff, I'm looking at the radar now (2130 PDT Monday) as showers are moving through but there is a static echo over Portland and Seattle. It's that an echo of the smoke?

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  32. Cliff
    Some rain here in the San Juans late this afternoon and this evening....but looking at the air quality reports still the air is reported to be unhealthy or very unhealthy....Cliff why has the rain not improved conditions???

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  33. Haha some of these people! You are a Weather God Cliff. But you are not THE Weather God. Thanks for the deets as always!

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  34. Just looked at that AIRNOW gauge...it is "unavailable"!!...have they given up too?lol

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  35. Weather models also fail in the winter when a layer of ice or snow is prevalent. This is a physical property because a change in the state of matter (ice or snow to water) pulls heat from the surroundings, thus perpetuating the cold conditions. The smoke effect seems similar in that weather models fail when not considering physical properties near the surface.

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  36. What is the height of the smoke layer? Is it possible to get above it, say, at 5600' elevation?

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