Sunday, September 13, 2020

How Often Does Visibility Go to Zero?

 The air quality situation remains very poor this morning, with the murk heightened by the mixture of fog and low stratus over portions of western Washington.  Red (unhealthy) air over Puget Sound, very unhealthy (purple) air over the coast and eastern Cascade slopes), and hazardous (dark purple) air over the Willamette Valley and southeast Washington.  


The values in the Willamette Valley are frightening---many with an AQI over 400-- and the combination with fog has resulted in extraordinarily low visibilities.   Local weather enthusiast, Dr. Peter Benda, brought Eugene, Oregon to my attention, where visibility dropped to ZERO miles (see below).  You don't see that very often!


There will be only slight improvement during the day today, but tonight the models are emphatic that onshore flow will provide some relief.  The NOAA HRRR-smoke model shows poor air quality over Puget Sound at 11 AM today (see below) and worse over the Willamette Valley and eastern WA and Oregon.


But by 9 PM tonight, the promised relief is on the way, with cleaner air pushing in from the west.  


And by 11 AM on Monday, serious relief will be at hand:


I should say that one encouraging sign is the thinning of the smoke over western Washington that is evident in the latest visible satellite image, with the densest smoke being blown to the east (see below).  You can event see the fog layer.


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12 comments:

  1. Great! But you don't answer MY question -- can we get out of this still by driving up to, say Mount Rainier or Steven's Pass?

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    1. Check the WSDOT and National Park Service webcams at those locations. Didn't look good to me.

      https://www.wsdot.com/traffic/passes/camera.aspx
      https://www.nps.gov/mora/learn/photosmultimedia/webcams.htm

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  2. Yesterday, it was bad as Tacoma's air was very much brown/orange and was like that all day even when it went to partly sunny in the afternoon as the sun was so obscured that I only noted it was out by a red/orange glow glinting off my car's windshield, but could not see it due to the angle from my office in my house. I had to go outside to actually see the red ball in the otherwise murky skies.

    This morning, it's way better, yeah, can still see that there is smoke, but considerably better than yesterday and it was obvious we had fog and it was quite thick and the skies now look more or less normal, though still smokey, just not as bad.

    It got chilly here, 48/49 at 5am, and it's still in the 50's, which is 54F at 11:00 AM. Oddly enough, Accuweather (HA!) is saying 65 for the highs, but the Weather Channel is still saying 71F earlier, but now says it'll top out at 67F, more like it.

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  3. Here in east auburn, lea hill area at elevation of about 475. Yesterday morning we were at 250 AQI, then dropped to around 200 AQI for most of the rest of the day. But today we started at 250 AQI and are now up to 260 AQI.

    Been coughing a lot today and allergies are going crazy (itchy eyes, stuffy nose, etc).

    Inside our house we are up to 40 to 50 AQI now. Yesterday we were under 30 AQI inside. So definitely getting worse!

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    1. what are you using to measure AQI in your house?

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  4. Thanks for the daily posts Cliff

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  5. I understand how the temperature increases from the easterly winds by pressure from coming over the mountains, but why does the humidity drop to single digits? It’s not that low coming from the eastern side of the state.

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  6. What about the predicted rain, supposedly arriving late Monday, with more on Tuesday?...That was going to be our savior...but no mention of it today!...Here in Everett, the AQI has been steady, at nearly 200....at one am right now, no Westerly breeze....getting tired of all this!

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  7. Port Angeles is measuring worse this morning (Mon 4 am) than last night when I went to bed. It's 261 now and was under 200 then. PLEASE tell me the wind is just later than expected! I can hardly breathe outside. I truly feel for those over 500 in Oregon!

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  8. I'm not seeing any serious relief whatsoever. Values on the coast are still in the 200 to 300+ range. The promised rain is not coming, this is not going away.

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  9. You'd better believe AQ is still very poor in the Willamette Valley! Thanks for the facts Cliff. The models depicted at firesmoke.ca/forecasts seem to be way off re AQ in WValley!

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