Wildfire Smoke, Heat Forecast Next Week In Western Washington

SEATTLE — Those enjoying the cool and rainy weather in Puget Sound this weekend should relish the moment, as early forecasts for next week raise the specter of a reunion with wildfire smoke and dry heat.

In the near term, Saturday should be even cooler than Friday, with good cloud cover, another chance for rain, and afternoon temperatures topping out in the high 60s. Sunday will bring another small chance for morning showers before things get a little sunnier as temperatures climb into the low 70s. Monday looks to be pleasant, with plenty of sunshine and highs in the mid-70s.

The real shift is expected to arrive starting Tuesday when forecasters say models are in agreement that a warming trend will begin, with temperatures creeping into the 80s. If early projections hold, afternoon highs will reach the high 80s by Wednesday, and draw near to the 90-degree mark Thursday. Exactly how hot temperatures will land late in the week depends on a few factors, and forecasters will get a better idea nearer to the event.

Air quality forecasts also show indications for wildfire smoke in Western Washington around the same time frame, with favorable odds for easterly winds developing at the surface level by mid-week. According to the Puget Sound Clean Air Agency, the shift in the winds could begin Tuesday or Wednesday, filtering in smoke from wildfires burning in Canada and east of the Cascades.

"Weather models show a high pressure system passing over our area starting next Tuesday," wrote Graeme Carvlin, an air resource specialist with the PSCAA. "This may change wind patterns near the ground from westerly, which brings in clean ocean air, to northerly and easterly, which could bring in smoke from British Columbia and Eastern Washington. The strongest northerly and easterly flow is predicted to occur on Wednesday and Thursday next week."

Forecasters are closely monitoring the level of impact for air on the ground, but current long-range predictions show air quality degrading to the "moderate" range by Tuesday in King, Kitsap, Pierce and Snohomish counties. Carvlin noted the models were still changing significantly, and predictions tend to be most accurate within two days. An update to the smoke outlook is expected early next week.

Smoke and air quality resources:

• Washington Smoke Blog
• Daily air quality forecasts
• Wildfire smoke preparedness tips
• AirNow's live smoke and air quality maps

With a few days' notice, residents have some time to prepare for the potentially unpleasant air ahead, and local agencies have a few pointers for dealing with wildfire smoke.

Tips from the Puget Sound Clean Air Agency:

• To limit your time outdoors, stock up on necessities like food, medications, and other items you may need for your family.
• A high-efficiency HEPA filter used in your air cleaner or HVAC system can help keep your indoor air clean.
• You can also make a filter fan to help clean your indoor air. All you need is a box fan, furnace filter (MERV-13 or better), and a bungee cord or tape. (Step-by-step instructions here.)
• Designate a room in your home to be a “clean room.” This room should have as few windows or doors as possible, or they should be closed, to keep smoke out. Use an indoor air cleaner or filter fan to make the room even cleaner. Find out more here.
• If you have an air conditioner, close the fresh air intake if available so you can keep smoky air out of your home.
• Know where the nearest “cooling center” is located. Cooling centers, like libraries or community centers, can be a good place to avoid smoky air.

Find more wildfire smoke tips from Public Health - Seattle & King County and the Washington State Department of Health.