Saturday Night Update: Heavy Smoke & Unhealthy Air Quality Continue

No FastCast tonight…keep reading below for a smoke update.

Wildfire/Road Closure Update 11:15 PM Saturday:

For information on the Bolt Creek Fire, which is burning near Skykomish and Index, WA (20-30 mi. west of Stevens Pass), CLICK HERE. This fire has closed US-2 from Gold Bar to Stevens Pass, and has caused evacuations of the towns of Index, Grotto, Baring, and Skykomish.

US-12 remains closed from Packwood to Naches (SR-410 junction) due to the Goat Rocks Fire. SR-123 is also closed from SR-410 (Cayuse Pass) to US-12 (southern entrance to Mount Rainier National Park).

Cross-state travel is available over Snoqualmie and Blewett Passes, SR-20 and SR-410, and through the Columbia River Gorge.

Helpful links for wildfire updates are in the “Helpful Weather Websites” section of the blog. Additionally, stay tuned to NWS Seattle’s Twitter and the Puget Sound Clean Air Agency’s Twitter.

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Heavy smoke (both surface & aloft) moved north into Western Washington from fires in the Oregon Cascades. Air quality in the Puget Sound area is in the “unhealthy” category, meaning that it is recommended that all people stay inside. The AQI map below is from the AirNow app (available on iOS and Android).

Red means “unhealthy,” and this category now dominates the interior lowlands, including Seattle and Tacoma.

Let’s take a look at how long the smoke and degraded air quality will last.

The HRRR forecast for surface smoke at 8 AM Sunday is below.

Expect a continuation of unhealthy air quality and heavy smoke through the night and into the morning, especially in Whatcom and Skagit Counties, as heavy smoke from the Bolt Creek Fire moves NW.

By 5 PM Sunday, smoke will be moving to the east, as we will have fully transitioned to onshore flow.

Surface smoke will be on its way out of Western Washington, although it will likely smell smoky, with degraded air quality, through Sunday evening. Eastern Washington will be choked in surface smoke, with unhealthy air quality expected.

By 8 AM Monday, Western Washington will be free of surface smoke, except for the potential of isolated areas of surface smoke in the foothills.

However, air quality will likely be degraded in the Cascades and Eastern Washington, as smoke, heavy at times, flows eastward from mountain fires.

Smoke aloft will take a bit longer to clear, and will be quite heavy on Sunday morning, as seen below.

Notice the red colors over the lowlands. Red represents heavy concentrations of smoke aloft. This heavy smoke will likely elevate Saturday night’s lows (staying in the 60s), and lower Sunday’s highs to the upper 70s.

By Sunday evening, smoke aloft will still be over Western Washington, but the effect of onshore flow is clearly seen in the forecast, with smoke plumes from fires in the Cascades blowing east.

Smoke aloft will begin to slowly clear overnight for Western Washington, while remaining quite heavy over Eastern Washington.

By Monday morning, smoke concentrations aloft over Western Washington will be much lighter.

Western Washington’s skies will be nearly normal by Monday evening, with a slight hint of smoke aloft remaining. However, in Eastern Washington and the Cascades, dense smoke aloft will be present for the foreseeable future.

There is a slight chance of showers around Western Washington and the Cascades on Sunday morning and Sunday evening. While any rain in these showers would be a few drops to a trace, there is also a slight chance of thunderstorms. This is unlikely, but don’t be surprised if there is brief rain on Sunday.

The HRRR rain forecast above (through Monday morning) shows very slight rain accumulations (under 0.05”) in parts of the lowlands.

On Saturday, Sea-Tac Airport set a daily record high temperature of 92°, which means that 2022 officially has the most 90°+ days (13) in Seattle history. Saturday’s highs are below.

Highs around the region reached the upper 80s to mid 90s, hottest in the valleys east of I-5. Areas exposed to northerly winds from Puget Sound or under the Bolt Creek Fire smoke plume remained in the mid 70s to low 80s.