Note: Some users might notice intermittent discrepancies in colors shown on the map of air quality monitors above, and those reported on the Department of Ecology's official page. This is because Ecology believes their method of calculating the air quality category (i.e. “Good”, “Moderate”, Unhealthy” etc) is more protective of public health in Washington. If in doubt as to which better represents public health risk, use the more stringent of the two (i.e. the map showing worse air quality).
Wednesday, August 9, 2017
It's stuck until Friday at least
Last evening's satellite picture (~4PM) shows much of the state socked in with smoke. Apart from the movement of some high clouds, the animation looks almost identical to this image. In other words, the ridge is preventing any substantial air movement. Air quality degraded yesterday and prompted the reinstatement of burn bans in the Puget Sound region and the issuance of an air quality advisory in Southwest WA.
So the forecast is for more of the same on Wednesday and Thursday. Western WA will see air between Moderate and Unhealthy, with coastal areas showing Good air. Eastern WA will rarely improve beyond Unhealthy for Sensitive Groups.
Morning fog has been present close to water for a few days now (see background view in the Nisqually webcam) and should not be confused with smoke.
Though the ridge S-L-O-W-L-Y moves east of the Cascades on Friday, there is no strong intrusion of marine air to rapidly clear the smoke from western WA. While air quality will start improving by Friday evening, models suggest that it might be well into the weekend before on-shore winds are able gather enough steam to flush out the smoke (image below shows surface winds on Sunday morning). Eastern WA will take even longer to clear out.