Smoke Plume from the Bolt Fire Invades Western Washington

A narrow plume of relatively dense smoke from the Bolt fire has been pushing into western Washington the last few days.

And today may be the worst of the period.

The 11 AM surface air quality network run by Purple Air shows the smoky air (red colors are the worst) moving westward out from Steven Pass highway into Everett and north Seattle.  I can smell the smoke here at the UW.




The high-resolution visible satellite image this morning clearly shows the plume of smoke following through the relatively narrow Skykomish River valley and spreading out as it hits the lowlands.


Near sunrise this morning, the smoke plume was apparent looking northward by the Seattle PanCam.

Although not spread horizontally, the Bolt Fire is still smoldering and burning internally, producing significant smoke, as evident from WSDOT cams on Route 2.


The meteorology is interesting.

Cool air produced by the longer nights drains into river valleys (like the Skykomish) and then jets out into the lowlands, injecting the smoke into populated areas each morning (see plots of the amount of particles in the air above Monroe, WA the past few days).  Later in the afternoon, increasing mixing by convective mixing (produced by surface heating) tends to dilute the smoke concentrations.

A narrow plume of relatively dense smoke from the Bolt fire has been pushing into western Smoke Plume from the Bolt Fire Invades Western Washington

The meteorological "problem" is that we have a very weak pressure pattern over us right now, with little clean, onshore flow (see weather map for this AM, showing sea level pressure).

A narrow plume of relatively dense smoke from the Bolt fire has been pushing into western Smoke Plume from the Bolt Fire Invades Western Washington

Tuesday won't be much better, but the pressure pattern should change on Wednesday afternoon, with much more onshore and northwesterly flow moving in.

Comments

Post a Comment

Popular posts from this blog

Why so little lightning in the Pacific Northwest? And a very nice weekend ahead.

Image
During the past 24-hours, there have been a few lightning strokes over the region (see below) but nothing to write home about (see below). It turns out that the Pacific Northwest and the remainder of the West Coast have some of the lowest frequencies of thunderstorms in the entire country (see below). But why?    My podcast provides the answer. And I also give the weekend forecast....and I think most will like what I have to say. To listen to my podcast, use the link below or access it through your favorite podcast service. Some major podcast servers:     Like the podcast? Support on Patreon 
Read more

The Time of Year You Can See the Air Move

Image
  Most of the time, you can not see the air move.   You can feel it, but the complex, turbulent motions are invisible to you, except when it interacts with leaves and branches on trees and plants. But for a few weeks of the year, the sky is full of small, cotton-like tuffs that like a natural MRI machine reveals the complex three-dimensional motions of the atmosphere.   Cottonwood season.  And we right in the middle of it.   Being cottonwood aware is of particular value this year.  It reveals the active dispersion and movement of air that makes the outdoors essentially COVID safe, and thus should be of some comfort for those nervous about transmission outside. Cottonwood seeds are embedded in small cotton-like fibers.   A million seeds weigh about 3 pounds.  Yes, each seed and tuff weights about .000003 pounds.   And that fact, plus the cottonwood tuff, means that these seeds fall VERY, VERY, VERY slowly.   So slowly that they are excellent markers for the three-dimensional flow of the
Read more

A Much Colder Than Normal April: But How Unusual?

Image
  April was a chilly month over the Northwest, but how chilly?     It turns out the answer depends on where you are located. The difference between this April's temperatures from normal across Washington State (below) shows that the entire state was well below normal.  The eastern side of the state was particularly frigid:  some areas were more than 6 degrees below normal.   Considering the west side of the state, the April mean temperatures at SeaTac Airport are plotted below.   This April was the coolest since 2011. April 2020 was in 15th place for the coolest April since the mid-1940s and was a bit more than 4F below normal.  So if you felt that you were cheated out of normal spring warmth...you are right. But if you really wanted to experience extraordinary April cold you had to be east of the Cascade crest. Consider Yakima.  Wow.  It had the third coldest April temperature since the mid-1940s.   And the all-time record in 1955 was only slightly colder. If you want a longer-te
Read more