The forecast remains on track from this blog post. No update Thursday night.
A heat wave, surface and elevated smoke, and a chance of thunderstorms are all ahead for Western Washington. Light concentrations of surface smoke (along with moderate to heavy smoke aloft) will be present across Western Washington from early Thursday through at least Friday. This will bring degraded air quality in the “moderate” to “unhealthy for sensitive groups” categories in the lowlands. Use the link under “Helpful Weather Websites” on the right side of the blog for updates. Heat will peak on Thursday and Friday, with lowland highs in the low to mid 80s from Everett north and in the upper 80s to low 90s from Everett south. Temperatures decrease to the upper 70s to mid 80s (hottest south of Seattle and away from water) on Saturday, then down to the mid to upper 70s regionwide on Sunday. Low temperatures through Saturday will remain warm, in the low to mid 60s, which isn’t great due to potential degraded AQI. Additionally, there is a chance of thunderstorms in the Cascades on Thursday and Friday, with that chance potentially extending into the lowlands on Friday afternoon. Stay tuned for more information about that chance, and keep reading below for more information on the upcoming weather impacts.
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Continue reading the full blog below!
Smoke is heading back into Western Washington. The biggest contributors to the smoke will be the Williams Mine Fire (4,500 acres near Mt. Adams), the Retreat Fire (45,500 acres west of Naches), and for some of northern WA, the Calcite Creek Fire in BC.
We’ll start with the forecast for smoke aloft on Thursday morning from the HRRR model.
This forecast shows moderate to heavy concentrations of smoke aloft for Western WA and Western OR on Thursday morning. The sun will likely be very red across the region.
By Thursday evening, large plumes of smoke from fires in WA, OR, and BC are pumping tons more smoke into the atmosphere.
Take note of moderate to heavy smoke concentrations aloft from the Seattle area south through central Oregon. The plumes from the Retreat and Williams Mine Fires are producing large amounts of smoke across south-central WA.
By Friday morning, the smoke plume from the Williams Mine Fire is predicted to drape smoke aloft across Western Washington and Oregon.
This will bring quite a red tint to the sun across the region, and is also indicative of significant growth on the Williams Mine Fire.
Now, let’s shift gears from smoke aloft to surface smoke. This is what impacts AQI. Below is the forecast for surface smoke around midday Thursday.
By midday Thursday, light concentrations of surface smoke are present across Western WA, with moderate to heavy concentrations for the Portland metro area due to the Williams Mine Fire.
Next, here’s surface smoke by Thursday evening.
Notice the smoke plumes from the Retreat Fire and Williams Mine Fire are blowing westward into Western WA. This is the reason for light surface smoke concentrations that will continue through Thursday. Don’t be surprised if you smell wildfire smoke, with air quality in the “moderate” to “unhealthy for sensitive groups” categories.
Next, let’s take a look at the very hot temperatures for the next couple days. Below are Thursday’s highs from the NWS NBM forecast.
This forecast shows highs from Everett north reaching the low to mid 80s, and from Everett south reaching the upper 80s to low 90s. The Willamette Valley reaches the mid 90s, and Eastern Washington reaches the upper 80s to upper 90s. The coast will remain comfortable, in the upper 60s to mid 70s (isolated upper 70s inland).
Next, here’s Friday’s highs, also from the NWS NBM model.
Notice cooler temperatures moving inland on Friday, with the coast down to the mid 60s to mid 70s (hottest inland). Areas from Everett north will reach the upper 70s to mid 80s, while areas from Everett south will again reach the upper 80s to low 90s. The Willamette Valley will reach the upper 80s to low 90s, and Eastern Washington will reach the upper 80s to upper 90s.
One thing to note with temperatures is that smoke can keep temperatures a few degrees cooler than what is forecast, especially if it’s thick smoke aloft.
Finally, let’s take a look at thunderstorm potential on Thursday and Friday. Below is the European model lightning forecast for Thursday afternoon.
There’s a chance of thunderstorms for the Cascades, mainly from Snoqualmie Pass northward, parts of NE WA and the Oregon Cascades.
However, Friday is a different animal. Below is the lightning forecast for Friday afternoon.
The overall environment is very unstable on Friday, with high lightning potential for almost the entirety of the Washington Cascades, the Olympics, and mountains in Oregon including the Cascades and Blue Mountains.
Additionally, note that the thunderstorm chances over the Olympics spread into Central Puget Sound and the Kitsap Peninsula. Lowland thunderstorms aren’t out of the question with this setup.
Stay tuned for more information Thursday night, as this setup gets closer!
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