Things are trying much more pessimistic this morning, with significantly much less enchancment in western WA and OR air high quality than anticipated yesterday.
And these issues are highlighting points with our modeling techniques and talent to watch/simulation smoke within the decrease environment. Paradoxically, such issues are what modelers like me stay for, offering alternatives to be taught and enhance our techniques.
Air high quality has not improved in a single day, as proven by the abstract at Four AM this morning from the superb Washington State Dept of Ecology WASMOKE web site. Hazardous air over Puget Sound, the Willamette Valley, and components of Eastern WA.
The mannequin forecasts yesterday (HRRRSMOKE, Washington State University’s AIRPACT SYSTEM, the USDA Forecast Service GRAYSKY) have been suggesting enchancment by now….and it isn’t occurring. Even the specialists at WA Department of Ecology have been going for higher situations by this time.
But floor air high quality stays poor and on the very least just isn’t bettering as quick because the fashions prompt. Last evening I used to be nervous concerning the forecast and could not sleep well–and now that I see what’s going on, I’m going to surrender on my pillow.
I believe I perceive a few of the issues and what they indicate for the forecast. But earlier than I clarify, let me notice that forecasting smoke could be very new know-how and really troublesome for a number of causes. And the present state of affairs performs to a number of of our weaknesses.
Problem 1: A cool, secure layer of smoke close to the floor.
Air high quality has improved vastly above roughly 5000 ft, as robust southwesterly winds have developed aloft. Below that degree, chilly, smoky air is trapped by an inversion, a layer of the environment through which temperature warms with peak. Think of the inversion as a barrier to atmospheric motions, a cap to the vertical motion of air. It prevents the smoke from mixing out vertically.
This state of affairs is proven clearly by a plot of the balloon-launched radiosonde sounding at Forks, on the WA coast (see under).
Temperature is proven by the right-most stable line, dew level temperature by the left line. Height is when it comes to stress, with 700 being roughly 10,000 ft. Wind are proven by the vectors/pennants to proper (extra little line, the stronger the wind).
There is a cool, moist layer under roughly 5000 ft through which the winds are weak. About roughly 5000 ft (840 to 820 when it comes to stress in hPa), you may see the inversion, above which the winds are a lot stronger and from the southwest.
The bother is that the fashions usually are not precisely portraying the decrease dead-air layer, bringing too robust winds under the inversion and mixing out the smoke greater than actuality. Unfortunately, a basic downside with our forecast fashions, which we’re struggling to repair.
And it’s worse than that. The smoke itself is strengthening the inversion by stopping photo voltaic radiation (and thus warming) from penetrating to the floor and by warming of the higher smoke layer by the solar. Details we’ve to get proper.
Just to impress you with the power of the inversion, Sunday afternoon temperature have been within the mid-50s in Portland, whereas within the mid-70s round Mt. Hood (see under, click on to enlarge).
Problem 2: Smoke over the Pacific
We are actually getting onshore move aloft (and to a lesser diploma on the floor) and we’re pulling smoke that was ejected through the previous few days over the Pacific. 2-5 days in the past, an enormous quantity was injected offshore (see picture for Sept 11 under), and now a few of that smoke is being pushed again in, and the fashions have an unsure deal with on its distribution.
The outlook this week
This week is nice illustration why we want people watching the automated techniques. It like a airplane on autopilot that’s about to crash into the mountain–we must take over the controls.
The newest HRRRsmoke forecast continues to be bettering the air high quality too quickly, significantly over western Washington and the coast (see forecast under for three PM).
Reality is proven by the plot of small particles at Beacon Hill in Seattle over the previous 48h. We are in all probability previous the worst smoke concentrations and air high quality could be very slowly bettering. That might be the story for the remainder of at present. Slow enchancment. And it seems that this would be the story for Tuesday as nicely. I simply checked the most recent National Weather Service forecast discussion–they seem to have the identical tackle the state of affairs. Sorry.
One Encouraging Note
Let me finish with a optimistic. Although air high quality just isn’t bettering shortly, the decline in smoke above us yesterday is leading to extra daylight. Below is the photo voltaic radiation on the UW for the previous three days (Friday to Sunday). Friday had some smoke, however photo voltaic radiation was not abysmally low (15.49). The backside dropped out on Saturday (4.28), worse than most darkish, winter days. But Sunday was a bit bitter (8.86) and hopefully it brightened your spirits.
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