September Heat Gives Way To A Cooler Stretch: Puget Sound Forecast

SEATTLE — An unusually hot streak of late September weather is on track to wind down after Tuesday, but Seattle may log yet another heat record before the clouds settle in.

Afternoon highs at the Seattle-Tacoma International Airport hit 80 degrees Sunday, marking just the 20th time this late in the season in 77 years of records, according to the National Weather Service. Temperatures again cleared 80 degrees Monday, setting a new daily record.

Reaching 80 degrees two days in a row at this time of the year has happened just five other times on record, forecasters said, and hitting a threepeat would be a first. Monday’s dry heat also spurred a red flag warning through the evening across the west slopes of the Cascades due to elevated fire risks.

At the same time, smoke from existing wildfires made its way back over Western Washington, degrading air quality in portions of King, Pierce and Snohomish counties Monday afternoon. Fortunately, forecasters expect the remaining smoke impacts will clear out by Wednesday as temperatures cool and clouds return with a chance for rain.

The Puget Sound Clean Air Agency writes:

"We will have mostly GOOD and MODERATE air quality throughout the region on Monday and Tuesday. Eastern Snohomish and King County will experience some smoke from the Bolt Creek fire near Skykomish. The smoke has been clearing temporarily during the afternoon and returning overnight. This pattern should come to an end on Wednesday as a storm system will come through and help clear out the smoke. Note: Some smoke remains in Pierce County after being [pushed] southward yesterday and should clear by [Wednesday]."

Forecasters expect temperatures Tuesday afternoon will run similar to Monday, but may fall just short of 80 degrees. A change in the air should be apparent by evening.

"Increasing clouds Tuesday night will herald a frontal passage still expected for Wednesday," NWS Seattle wrote Monday. "Models still are not particularly impressed with this system as solutions remain consistent that it will fall apart to some degree as it moves eastward. However, as the upper low moves inland [Wednesday] afternoon and evening, precip chances will increase into the [30 - 50 percent] range for most locations, bringing the best [chances for precipitation that Western Washington] has seen in a while."

A chance for showers will stretch into Thursday as afternoon highs dip into the high 60s around Seattle. Friday and the weekend look sunnier and warmer, with a small chance the 80s will make a rare October appearance Sunday or Monday.

Here is the five-day weather outlook for the Seattle area:

• Tuesday: 77°/57° (Sunny/PM clouds)
• Wednesday: 70°/56° (Chance of showers - 30%)
• Thursday: 67°/52° (Chance of showers - 40%)
• Friday: 70°/52° (Mostly sunny)
• Saturday: 76°/54° (Mostly sunny)