Friday, August 4, 2017

Mild recovery started. And paused

The smoke column was slightly thinner compared to Wednesday.

But sadly the northwest maintains the ignoble distinction of recording the poorest air quality in the lower 48 states. Here's a map of 24-hr average fine particle levels on Thursday, overlaid with polygons of smoke plumes.

Here's an animation of the visible satellite just before sunset on Thursday- really amplifies the smoke sources. Notice how the upper level winds were blowing it eastward. Unfortunately that didn't make its way down to the surface and help ventilate our cities. And... light northeast winds have returned overnight 😒

Although there was a slight improvement in overall air quality yesterday compared to Wednesday, none of our sites managed to drop all the way down to Good. And the 72-hr forecast trajectories (green= 300ft above ground; blue =1500ft above and red= 3000 ft above) seems to suggest that new smoke will mostly stay east of the Cascades. Red triangles on the map are fire locations.

However there are reasons to believe that western WA will experience more smoke from BC over the coming days, perhaps a little less than before. Light onshore flow is expected each day but nowhere near enough to flush out the smoke. Be prepared for air ranging from Moderate to Unhealthy over the next few days.

Eastern WA will be impacted more from BC fires but winds will be stronger and help ventilate the Columbia Basin somewhat. Due to the many local fires, most sites- particularly near the Cascade foothills- will run from Unhealthy for Sensitive Groups and Unhealthy. Far eastern WA might be lucky enough to see some green dots (Good air quality) popping up on the map by Saturday evening.

Don't breathe the smoke while beating the heat! Remember to turn your air conditioners to recirculate mode and use a HEPA filter if needed. Minimize outdoor exposure. Sensitive individuals should wear N95 masks.

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