Smoke from Oregon drifts into Washington. Ends Monday.

Satellite imagery visible this morning shows a plume of smoke over Washington, with the smoke mostly originating in eastern Oregon.

The effects of the smoke were quite evident in western Washington, with a red sun rising in the east this morning:

The smoke is so thick that solar radiation has been significantly reduced (see Seattle measurements for the past three days below). That means we’ll be cooler today.

Air quality is good on the coast, fair in the western lowlands and Columbia Basis, and poor in eastern Oregon areas

Laser altimeters operated by the Puget Sound Clean Air Agency show smoke moving overhead. Here is an example from the device in Beacon Hill, Seattle. Time is on the x-axis (increasing to the right) and the y-axis is height in meters (3,000 meters is about 10,000 feet). A fairly deep layer of smoke is moving overhead.

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Almost all of the smoke comes from large, scattered grass, brush, and tree fires in eastern Oregon (see current fire areas below). Numerous lightning and human-caused fires have occurred in the eastern Oregon grasslands, along with other fires in the southern Oregon Cascades. Large, flammable, invasive grasses (like cheatgrass) are a real problem.

During most of the summer, smoke from the fires does not affect western Oregon or Washington because winds typically blow from west to east in our area.

But for the past few days, easterly winds have been dominant, related to a heat trough extending into western Oregon. To illustrate, here is a weather forecast map at 850 hPa (about 5,000 ft) this morning. The solid lines represent pressure, and you can see the wind symbols. Easterly winds are blowing across northern Oregon and southern Washington.

Below is the movement of air at the same altitude (5000 ft) ….something called rationalize. You can see why the smoke from eastern Oregon is coming toward us.

Fortunately, the situation will change within the next 36-48 hours.

Here are the streamlines showing the airflow at 5pm Sunday. The wind direction has completely changed…now from the northwest. That should blow the smoke away.

To show the improved smoke situation, I show the smoke forecast (total smoke in vertical columns) from the extremely efficient HRRR smoke prediction model.

This morning at 8 am. There is a lot of smoke.

Tomorrow morning at 7am, still smoke

But by 5 a.m. Monday, the shift to a northwesterly wind had taken effect, with western Washington nearly smoke-free. Tuesday should be even better.

Relief is coming!