Wildfire Smoke Alert for Western Washington and the Portland Area

Western Washington has avoided serious smoke throughout most of the summer, but that is going to change tomorrow, as hazy skies, red suns, and degraded air quality move west of the Cascade crest.

The current visible satellite image shows a substantial plume of smoke moving southeastward from a collection of fires over the north Washington Cascades (I put on an arrow indicating the plume)

Right now, eastern Washington is getting smoked up, but later today the weather pattern will change, with easterly (from the east) flow moving into Washington State.  As a result, the smoke plume will rotate and head southwestward towards Puget Sound.

Let me now show you the smoke prediction from the NOAA HRRR smoke model.

I will first present the vertically integrated smoke prediction, essentially summing up the smoke in a vertical column of air.  Smoke at the surface will be less.  But this is a good measure of how smoky the sky will appear.

At 5 PM today, most of the smoke will be east of the Cascade crest.

But by 4 AM tomorrow (Friday) morning, smoke pushes over Seattle and the central WA coast.   Many will awaken to a smoky sky.

And by 11 AM, the miasma will spread to the southwest WA coast and the northern Willamette Valley.

So hazy skies are a given, but what about poor air quality at the surface?  This can be determined from near-surface smoke predicted by the HRRR-smoke model.

At 4 AM tomorrow morning, surface smoke will have spread over the western slopes of the Cascades.

And by 2 PM Friday, smoke will have surfaced over much of northwest Oregon, central Puget Sound, and southwest Washington. 

A saving grace for Seattle will be the low-level northerly flow from northwest Washington that will be relatively clean.  The smoky air will ride over it.

The smoke will be in place for most of Saturday as well, with increased low-level smoke on Sunday morning (3AM shown below).

If you are sensitive to wildfire smoke, this is the time to prepare.  All our COVID preparations can be used to lessen smoke exposure.    If you have an air filter machine, you can run it in a small room to clean the air.  You can wear an N95 respirator mask.  If you have a box fan, tape a good furnace filter to it and use it in a small room.   

By later Sunday, the smoke situation should improve.  An unknown is whether new fires will be started on the west side of the Cascades during the next two days--and that will be up to all of you.