Sunday, August 19, 2018

Smoke Now Pushing Into Western Washington

During the next 12 hours there should be a major influx of wildfire smoke into the lower elevations of western Washington.

The MODIS satellite imagery around noon showed very dense smoke over eastern WA and the north Cascades, with lesser but substantial smoke now over northwest Washington, with a thinning from Seattle southward.


The 2PM image from the GOES geostationary satellite, indicates the smoke is slowly moving southward west of the Cascade crest.

The backdrop of Seattle is getting murkier over time.

As of noon, air quality was moderate over the Puget Sound area, except for rapidly worsening conditions at Darrington (see below)


Unfortunately, if our models are correct, low-level air quality is about to get much worse.  The NOAA/NWS HRRR smoke model prediction for near-surface smoke showed high values (red-purple) over the Cascades and eastern WA at noon (1900 UTC)

By 5 PM it is moving into Puget Sound

And fully entrenched at 5 AM Monday. These forecasts are for higher concentrations than in the forecasts for last Wednesday, our last big smoke day.


 The movement of smoke will be supported by a change in the winds aloft.  The following maps the predicted winds (barbs) and temperature (color) at around 5000 ft (850 hPa).  Major strengthening of northerly to easterly winds during the next 24 h.  The first map is for 11AM Sunday....weak wind from the SE.

 By 11 PM, moderate NE winds will be blowing smoke right into us.
 And easterly flow will be in place at 11 AM Monday....pushing the smoke our way.  Not good.

So get rid for a major smoke event.   No, I am not going call it Smokezilla.



Saturday, 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.


_______________________________

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.


Friday, 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.

Wednesday, August 15, 2018

Seattle's Worst 24h Air Quality on Record

Air quality in western Washington is very poor right now.

Incredibly, in central Puget Sound it is probably the worst in the nearly two-decade observing record of the Puget Sound Clean Air Agency for any time of the year.

I have been here a long time and I have never seen anything this bad.  The view from the Seattle SpaceNeedle Panocam is murky (see below)


And the view from my department is very limited...no mountains and can't even see across the Lake.


But now, let me really impress (or depress) you.  Below is a plot of 24-h average particulate concentration (PM2.5) in the atmosphere at the Puget Sound Clean Air Agency Duwamish site in Seattle.  The past 24-h was the worst on record for any time of the year.  Number two was the smoky period last summer. 


Historically, Seattle has its worst air in the winter from wood smoke and other combustion products, but today and last year were summer maxima from wildfires--very different animals.

The observing site in Tacoma also had its record in the past 24-h hours.

So why did our near surface air quality get so bad so fast?  

Fires were burning for quite a few weeks in British Columbia, California and eastern Washington, but western Washington had clean air at low levels (off the Pacific) with smoke aloft.  But on Monday, surface high pressure started to build in north and east of us (see map), resulting in easterly and northeasterly flow over the Cascades that brought the smoke over and down the terrain into western WA--allowing smoke to get to the surface.

Surface map at 8 PM Monday
I ran some low-level air trajectories ending in Seattle at 11 PM Tuesday night (using the NOAA Hysplit system).  Air ending at 100 meters above the city came from smoky BC, while air at 1000 meters were from eastern WA--both sources of smoke.



High pressure aloft amplified just offshore, resulting in strong downward motions in the lower atmosphere, which produced a subsidence inversion from the surface up to about 3000 ft.   The inversion (temperature increasing with height) was very obvious in the balloon soundings at Quillayute, on the WA coast, and from the Seattle profiler (see below).  Inversions act as atmospheric lids, preventing the smoke from mixing out during the day.


In short, we had the "perfect storm" for wildfire smoke around western Washington.  Lots of fires around us, a meteorological situation that pushed the smoke to low levels, and the development of an inversion that kept the smoke in place. 

As I write this (10 AM), the air quality  in Seattle is getting even worse (see plot)


EPA's AIRNOW site provides the five worst air quality locations in the U.S. each day.  Well, today the Northwest possess ALL FIVE of these sites:


Chelan has a startling value of 211, with the rest right behind.

Incredibly, historically bad air and unhealthy for all.  No running for me today.  Expect very slow improvement on Thursday.




Tuesday, August 14, 2018

Smoke Storm Hits Washington State

The rising sun this morning in Seattle has that other worldly red-yellow color and a thick haze lays over western Washington.

The reason?  Massive amounts of smoke has made its was southward from the wildfires in British Columbia and westward from the several fires in eastern Washington.
Seattle at 6:23 AM Tuesday.  Can you see the sun?
A video drone ascent on northern Kitsap (provided by Greg Johnson of Skunk Bay Weather) dramatically shows the murk:


The latest Washington State Air Quality Map shows unhealthy conditions over western Washington, with some locations (like Port Angeles, Cheeka Peek near Tatoosh, and several locations on the eastern slopes of the Cascades) reaching very unhealthy and hazardous conditions.


In fact, air quality is better in Beijing right now (see graphic)


Yesterday's noon image from the NASA MODIS satellite over the region was stunning.  You can see the smoke moving into western WA from Canada and eastern WA and there was an amazing, long smoke front over southern Washington.

Here is Seattle (Puget Sound Clean Air Agency Duwamish site), the smoke (PM.5) surged yesterday afternoon, peaking this morning to around 80 mg per cubic meter (1-hr average).


This was by far the highest value this summer.  To give you some context, here is the same plot since late May.  Nothing close.  There was a minor peak on July 4/5 of about 1/3 the value.


Solar radiation is being substantially reduced by the smoke.  Here are plots on the UW Atmospheric Sciences roof for yesterday and August 9th (before the smoke).  Down about 14%.  The result will be substantially cooling of today's highs by at least 5 F based on recent experience with our WRF model.
.

 The densest smoke is found at the lowest elevations.  Paradise (5500 ft) is on the edge and Camp Muir (about 10,000 ft) is above the gunk (see picture)



The good news is that low level air quality should improve later today over Puget Sound and NW Washington, as suggested by the latest forecast of the NOAA/NWS HRRR smoke system.  But smoke will return eventually.


And as I will talk about in a later blog, smoke forecasting has improved dramatically in recent years, giving meteorologists a powerful tool in warning folks of degrading air quality from wildfires.