Tuesday, August 10, 2021

What’s the problem with a little nice weather?

You may have seen the forecast for another heat wave this week.  While temperatures in the 90s already elicit groans from native PNWers, there is another reason to wag your finger at the heat.

High-pressure systems not only lead to high temperatures but also move air in a clockwise direction.  This can bring in smoke from Northern CA and move smoke from Eastern to Western WA.


Currently, Washington fires aren't putting out that much smoke. Western WA could see some smoke from the Schneider Springs fire NW of Yakima on Thursday or Friday with the easterly winds. But one of our generally better performing models, the HRRR, has the smoke staying upper level for now. So, we aren’t expecting a lot of Central/Eastern WA smoke crossing into Western WA this week.  Of course, the local impacts of those fires will continue to be significant and people living near the fires should take precautions.

Highlighted in this image are the Schneider Springs fire northwest of Yakima and a collection of three fires on the Colville Reservation.

In contrast, fires in northern CA are putting out a whole bunch of smoke.  Check out this satellite image from this morning.


The smoke is starting to pool off the coast and could be brought northward with the clockwise rotation of the high-pressure system starting Thursday. It will take some time to make it up here so we may begin to see hazy skies late Thursday or Friday. However, that smoke is staying upper level for now.

Overall, we expect mostly high-level smoke Thursday through Saturday with minimal impacts on the ground.  Strong westerly winds are predicted to return by Sunday, which should help clear out any smoke.

And last but definitely not least, expect MODERATE to UNHEALTHY FOR SENSITIVE GROUPS ozone levels near the west side of the Cascades on Wed-Sat due to high temperatures brought on by the aforementioned high-pressure system.

33 comments:

  1. When you say that the smoke will stay "high-level" ... what elevation? I'm trying to estimate how much smoke will be at 7000 ft near Leavenworth (the Enchantments area).

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    1. Hi David, that area wont be downwind of any local fires (barring new fires), but rather transient CA smoke could be present by Saturday-ish. I'd prepare for Moderate/ Unhealthy for Sensitive Groups air quality.

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    2. Interesting about the CA smoke. I can't find any of the forecast animations that go past Saturday afternoon. They all seem to say that the smoke will be Moderate (sometimes even slightly better than in Seattle). But I worry that the models are showing "surface" smoke, and I'm not sure if "surface" means the local surface (so, 7k ft in the Enchantments), or it means "low elevation", and thus isn't predicting the air at 7k feet very well? We'll be in the Enchantments area from tomorrow (Thur) through Monday. Are you saying to expect high elevation smoke starting Saturday? Will that continue in to Sunday and Monday also? (Thanks so much for replying to these comments! :-)

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    3. Hi David, "surface" means local ground level irrespective of ground elevation. So today's round of long range models have backed off on the CA smoke influence a bit more and are not bringing much of that to ground level around the Enchantments beyond Friday. So Moderate might be all you have to contend with until then. Enjoy the colorful sunsets courtesy of smoke aloft.

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  2. Hi there! Will the air quality and conditions be quite bad at the Cascades Pass Trail this week?

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    1. Hi Jessica, we're not expecting anything much worse than Moderate in that area this weekend. Please keep an eye on the forecast map at the top of this blog. Enjoy the hike!

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    2. FYI the Cascade Pass trail is closed due to a road wash out.

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  3. Thank you for keeping us updated! So appreciative of this resource.

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  4. Is staying inside with AC on a good way to product from ozone, or will ozone still just be sucked into the AC?

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    1. Hi Techforest12, good question! For the most part, yes, but...

      If your a/c has an activated carbon filter, then little ambient O3 will get indoors. However air also enters homes whenever doors are opened, and through infiltration. A paper by Abbass et al (2017) available at https://doi.org/10.1016/j.buildenv.2017.04.007, describes the fate of ozone once it is indoors. It is deposited on wall surfaces and can be taken up by indoor plants, thereby reducing the levels. However ozone also reacts with organic compounds present indoors, such as those from aerosol sprays, offgassing from carpets etc, to produce a different set of VOCs which may or may not be more toxic than the parent VOC. These reactions will result in a drop of indoor O3 levels, but the cumulative toxicity of the reaction products is hard to predict.

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    2. Hi techforest12, I would just add that the many AC systems don't have outside air intakes, so obviously they won't pull in ozone or smoke. For example, most window units and ductless/heatpumps don't have air intakes. So, it really depends on your system.

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    3. Thanks to you both for the info. I just did a little reading on AC units here:
      https://www.epa.gov/indoor-air-quality-iaq/wildfires-and-indoor-air-quality-iaq

      "Know how to adjust your HVAC system or air conditioner to keep smoke out

      ...If you have a portable air conditioner with a single hose, typically vented out of a window, do not use it in smoky conditions because it can result in more smoke being brought inside. Consider other cooling options like a fan or window air conditioner. If you have a portable air conditioner with two hoses, make sure that the seal between the window vent kit and the window is as tight as possible."

      I have a single hose unit and a dual hose unit. If I am understanding what you said correctly, both of these are considered "Duct ACs" and therefore will bring air in. However, the last sentence of the above quote sounds like dual hose might be acceptable assuming I've sealed everything properly?

      I'll do some more reading, but figured it was worth asking since other folks might be wondering the same.

      PS: A quick google for "ductless AC" looks expensive (yikes!), but sounds like a great solution for hot/smokey days indoors.

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    4. Hi techforest12, good question about the portable air conditioners! Yes, the single hose ones will pull in outside air, while the dual hose ones, if installed and operated correctly, shouldn't. So, using the dual hose one should be fine. The single hose will draw in some outside air, but it's tough to say exactly how much, or how much worse it will make your indoor air. If you have a good filter setup (e.g. box fan, etc) you could easily filter the smoke out fast enough to compensate for the leakage, but that would depend on a bunch of specifics for your setup, so I wouldn't recommend it, in general.

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  5. Hi there, thanks for this resource! What do you think the smoke visibility and safety is for Diablo Lake and Picture Lake on Friday/Saturday?

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    1. Hello, we're not expecting anything much worse than Moderate in that area this weekend. Please keep an eye on the forecast map at the top of this blog.

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  6. I had camping plans down by Adams (takhlakh lake) tomorrow through Sunday and from what I've seen it looks like the near-surface smoke will be bad there from the local fire - do you agree? I am going to cancel on the assumption it will at best be "unsafe for sensitive groups," but you are the experts and I would love your thoughts if you have time.

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    1. Hi Madeline, yes, that area wont be spared of smoke from the Schneider Springs fire (https://inciweb.nwcg.gov/incident/7775/), so periods of USG air are expected between today and Friday. Saturday and Sunday will see mostly Good air courtesy of a wind shift, if you want to consider postponing.

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    2. Thank you so much!! Very helpful.

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  7. Hi there!
    I'm co-leading a Mountaineers scramble in the Sunrise area of Mt. Rainier National Park on Saturday. Do you have a forecast for that area? The closest forecast I can find is for Enumclaw, and we'll be up at 6-7000 feet.

    We will not go if the AQI is unhealthy, and since I have asthma, I won't go if it's predicted to be USG due to wildfire smoke. Ozone doesn't seem to bother me as much.

    Thanks,
    Anna

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    1. Hi Anna, there's a lot of smoke out there from multiple directions and sources, and it's swirling around, for lack of a better description. So it's a tough forecast at this point. That said, I would expect that Sunrise will have USG (or worse) from wildfire smoke on most of Saturday. There's a chance we'll get some clearing later Saturday and it'll drop to Moderate, but I wouldn't plan on it right now. I suggest checking back tomorrow...

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    2. Thanks! I'll check back tomorrow. Appreciate it.

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  8. I'm seeing what look like 2 different smoke forecasts for the north Olympic Peninsula area. Most of the near surface readings look very bad over the next day or so, but the forecast map still has us in the green all the way through. Am I missing something? Many thanks!

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    1. What site is showing bad air on the Olympic Peninsula? Forecast and monitors look good for that area.

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    2. https://www.airnow.gov/?city=Agnew&state=WA&country=USA has changed predictions for today to USG and moderate tomorrow.

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    3. Also https://airquality.weather.gov/probe_aq_data.php?latitude=48.1052&longitude=-123.2454 shows some radical bad changes in store.

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  9. Hi,
    We are at Crystal Mountain Ski resort camping. The smoke is very thick this morning. Will it get any better today?

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    1. The Schneider Springs fire is near there... and pumping out a lot of smoke today. It should get a little better with daytime mixing, but expect more smoke. https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G17&sector=pnw&band=GEOCOLOR&length=24

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  10. Hi! I commented before but i don't think it posted, so if you see two comments from me, i am sorry. I live in Port Angeles and it is really smoky here right now. The haze is really bad and you can smell the smoke but the maps and air quality posts show us still in the green at 41. Do they not update the air quality very often? I have seen one air quality report from Cheeka Peak that showed levels over 100 and that is less than an hour from here. Thanks for any info!

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    1. Hi Linds--the air quality is updated hourly. Data from the most recently completed hour is collected from the monitor and displayed shortly after that hour is complete.

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  11. Central WA (Ellensburg) here, and wow it's smoky all of a sudden over here today. I couldn't tell if the above forecasts were just for western WA or if I missed a Central/Eastern WA impacts, but I'd love to know what the week is looking like for if the smoke will get worse/when it might clear out? Thanks so much.

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    1. The E. WA forecast is at https://wasmoke.blogspot.com/2021/08/breaks-over-for-eastern-washington.html. Friday is looking rough, but the cold front Sunday will help most of the east side.

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    2. There is a more recent post you should refer to, but expect more smoke tomorrow. Saturday/Sunday should see things clear out. Though, you are close enough to the Schneider Springs fire you could see intermittent smoke impacts, depending on what that fire does. https://inciweb.nwcg.gov/incident/7775/

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