July 31, 2020

Smoke Reaches the Northwest, High Temps in Eastern WA, and Marine Air is Poised to Move In

Smoke is now covering the Northwest, but most of it remains aloft.  The haze was obvious this morning from the SpaceNeedle Pano Cam, as was some mid-level instability clouds (altocumulus and altocumulus castellanus for those of you who enjoy cloud names).

But it was in  early morning satellite imagery that the smoke was really evident.  Thursday's mornings visible satellite image around 6 AM showed the smoke clearly (the hazy stuff), with a few mid-level cumulus as well.  Stark shadows of the clouds on the smoke.

The National Weather Service HRRR-smoke model shows the distribution of smoke aloft at 5 AM this morning, as diagnosed by their system.  You see the red area near the Oregon/California border?  That is the huge July Complex Fire, which now covers 82,000 acres, and is the biggest source of regional smoke. Such smoke rises and spreads out aloft.

We do have some local fires, but those are small and generally under control, and not major sources of regional smoke.  But the regional fires are the ones to really worry about, because they can bring smoke down to the surface.

Washington State's Department of Ecology has a wonderful wildfire smoke website and here is graphic from it, showing local air quality.   Western Washington has clean air, but air quality has declined along the eastern slopes of the Cascades due to both some local fires and CA smoke surfacing.

Moving beyond smoke, yesterday was an extremely warm day in eastern Washington, with a number of locations getting ABOVE 110F (see map below of Thursday's highs, click to enlarge).  One site near Moses Lake got to 112F and temperatures above 100F hit the slopes of Cascades. The temperature at Hanford WA (HMS) spiked to 113.2 F late yesterday afternoon around, tying their all-time record high temperature set previously in Aug 1961, July 2002, and July 2006 (records there extend back to 1945).  

Keep in mind that the highest temperature EVER in Washington State is 118F, at Ice Harbor Dam near the Tri-Cities.  Several locations tied or exceeded their daily records.

Well, everything is about to change.

Marine air is starting to push into western Washington and temperatures are 5-8F cooler than yesterday around Puget Sound, much cooler than that near the coast.  So instead of hitting around 90F, temperatures should top off in the lower 80s in the interior of western Washington.  And much cooler tonight.

The passage of marine air across the Cascades will produce strong winds east of the Cascade crest.  With warm, dry conditions in place, this situation will produce dangerous wildfire conditions,  resulting in extremely high values of the USDA Forest Service HOT-DRY-WINDY index (see forecast of this parameter at 8 PM tonight).  Reds and browns are very hight.  

I am sure Washington DNR and the Forest Service folks are getting ready for this.  Fortunately, all the fires on the eastern WA slopes are contained now, but we all have to make sure there is no ignitions.


  1. Today's minimum temperature at my location in NW Bellingham was 64F. This is the warmest daily minimum temperature I've measured since at least the summer of 2018 and one of the warmest daily minimum temperatures in my 5-year period of record.

  2. Cliff, this morning around 7a.m.I noticed the clouds moving over the south sound from southeast to northwest. Why?

  3. at about 5 in the morning i heard rain on the roof... national weather service posted a 20% chance for thunderstorms that night also.

  4. Welcoming cooling temps and praying for some moisture for the fires all over the state. Here west of Port Angeles, we have a around 60 acre fire that has shut of access to half of Lake Crescent in the Olympic National Park. Many Helicopters and float planes are here battling a steep fire on the Northeast shore of the lake in steep thick timber. One of the National Park's gems all caused by a careless individual(s). Thank you to the many agencies on the ground and pilots scooping water from the lake trying to get this mess contained.


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