August 18, 2018

A Smokestorm is Imminent for Western Washington

Sunday 9 AM update

The smoke is moving in aloft (see satellite picture).  This movement will accelerate later today.  Smoke will surge in first aloft and then down to the surface. Air quality is still moderate near the surface.  More later.


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You have heard of rainstorms, snowstorms, and windstorms.  It is time to create another one:

the smokestorm. 

And tonight and tomorrow one will hit western Washington, with air quality degrading rapidly to levels that may even be worse than Wednesday of the past week.  Vulnerable folks need to be prepared for this onslaught of smoke.


Large fires are now burning in British Columbia and eastern Washington, injecting substantial smoke into the air.   With generally westerly flow aloft during the past few days, western Washington has been protected, but the winds aloft are turning northerly and northeasterly, resulting in the smoke blowing directly towards us.

The visible satellite image around 10 AM Saturday shows lots of smoke over eastern WA and southeastern BC that is extending to the Cascades and even NW Washington.  Animations show this smoke moving directly towards northwest WA.  Low clouds are evident along the coast.


The MODIS satellite imagery around noon Saturday shows the approaching smoke more clearly:


Want to see something that is really amazing?  The smoke is dense enough to be picked up by the NWS weather radar (at Camino Island).  Here is an example around 12:30 PM Saturday, showing composite reflectivity (the highest amount of returned signal in the vertical column that is being sampled by the radar).



High resolution models predict increasing northeasterly and easterly flow aloft, bringing the smoke into us.    Let me show you the current forecasts from the NOAA HRRRSMOKE system for the next 36.

First,  vertically integrated smoke (total smoke in a vertical column).  Red indicated large values and purple is extremely high.

At 5 AM this (Saturday) morning, all is good in western Washington, but high values loom to the north and east.


By 5 PM Saturday, smoke is really moving into NW Washington.


By 5 AM Sunday most of western WA is covered with some very high values extending into northwest Washington from the fires on the other side of the Cascades.


 Even worse by Sunday at 5 PM.


Now that is vertically integrated smoke....smoke that makes the sun dim and hazes out our views.  Much of this smoke is aloft. What about smoke at the surface?    Let's take a look!

5 AM Saturday--a little haze but nothing serious.


Things are getting worse by 5 AM Sunday, particularly above roughly 1000 ft.


And substantial smoke reaches the surface by 5 PM Sunday.


Although HRRR smoke only goes to 36h, I suspect things will get much worse on Monday.  The UW WRF model predicts strong easterly/northeasterly flow at 2 PM Monday (see map at 850 hPa--about 5000 ft).  The gunk will be streaming over the mountains right into us.  Not good.


Monday could be an extremely smoky day and I expect that my colleagues in the National Weather Service will put out an air quality alert today.   They won't use the term smokestorm, but the threat to vulnerable folks will be serious.  One exciting aspect of the recent smoke events is the quality of our new smoke models and our ability to warn folks of such serious, health-challenging events.  If you can't stop the fires, you can at least warn folks about the smoke impacts and allow them to take protective steps.

Finally, an excellent place to go for real time air quality information here in Puget Sound is the Puget Sound Clean Air Agency.   The EPA AirNow site is also excellent.


August 17, 2018

Air Quality if Far Better in Western WA But Smoke Will Return

Take a deep breath.  It's ok.

Air quality has greatly improved at low levels over western Washington as cool, clean marine air has pushed in at low levels.   You can see this with a plot of the concentration of small particles in the air (PM2.5), the kind that can move deep into your lungs (see below for Seattle-blue color, Bellingham-red color, and Tacoma-yellow)

From the Puget Sound Clean Air Agency Website
Our air is by no mean pristine, with more particles than normal, but Seattle and Tacoma are at levels about 1/10th as high as Wednesday.  Bellingham is better, but they are closer to the BC fires and getting hit by some smoke this AM (but still down).

The excellent NOAA/NWS HRRR smoke model is predicting improving air quality at the surface during the next 24-h, something made clear by comparing the forecasts between 5 AM today (Friday) and tomorrow (see below, red is bad air, improving towards green, blue, and white).  Worse but still improving over the eastern slopes of the Cacades.



So Saturday's air quality should be decent as well. 

But then things change.  Upper-level high pressure builds in along the BC coast, coupled with a low-level trough of low pressure moving northward into western WA.  As a result, we will develop easterly and northeasterly flow in the lower atmosphere, bringing smoke back into the region.  This is well illustrated by the forecast winds and temperatures at 850 hPa (about 5000 ft) for Monday morning at 2 AM:



The NASA GEOS-5 model shows plenty of smoke blowing south over us on Monday at 10 AM (see map)

So enjoy the clean air, things will degrade by Monday.

Lowland Fog Season

The visible satellite image this morning was an October classic:   Low clouds (stratus and fog) within the valleys of western Washington, Or...