A Smokestorm and Heatwave in Western Washington This Weekend

It is a well-known saying that it is darkest before the dawn.

Well, it appears it will also be most smoky before the rain.

This weekend is going to bring a mix of record-breaking temperatures and smoky air....a situation that will probably be more unpleasant than today.

The visible satellite image this morning around 9 AM showed a lot of smoke heading into northwest Washington


And later in the day (5 PM shown) air quality over much of western Washington, and particularly Puget Sound, was marginal (red colors). I noted the odor of fire at the UW this afternoon. 

 Temperatures climbed into the mid-70s around western WA, with even higher temperatures in the foothills of the Cascades and Olympics (from warming downslope flow).



But the situation is going to get warmer and smokier this weekend.

With high pressure building to the east and a trough of low pressure extending up the West Coast, a moderate offshore pressure difference (higher inland, lower coast) will result in easterly (offshore-directed) winds. This easterly flow will warm further on the western side of the Cascades and coastal mountains.


This situation has its dangers.

On Saturday, as warm, gusty easterly flow surges westward, the dry winds will be particularly strong near the Columbia Gorge, something illustrated by this graphic showing the HOT-DRY-WINDY index.

We will all have to be careful not to start wildfires over northwest Oregon and southwest Washington.

The warm, dry air will spread over western Washington on Saturday with increased winds on the western slopes of the Cascades. The current fires (e.g., Bolt Creek) will rev up with more smoke.

High temperatures will hit 80F at many locations around western Washington--about 20F above normal.

And smoke will be wafted first eastward and then westward, reducing air quality.

To illustrate, let me show you the forecasts from the NOAA HRRR smoke model. Starting with the total smoke in the vertical, at 5 AM Friday smoke will first pour into eastern Washington and Oregon.



But by 11 PM Friday the smoke will push toward southwest WA and northwest Oregon and begin pushing westward across the Washington Cascades.



And then on Saturday morning, the smoke will surge into western Washington.


Much of the smoke will be aloft, producing a red sun, but some of it will reach the surface, as illustrated by the predicted surface smoke at 3 PM Saturday. 

 I may skip running that day.

But the dawn is coming, and the latest forecast indicates a radical change to cool, wet weather the next weekend.

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Announcement:  I will be doing a special online (zoom) session with my Patreon supporters at 10 AM Saturday.  I will discuss the extended forecast and answer your questions.

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