A change in wind patterns Saturday is expected to push wildfire smoke that’s fouled Pierce County’s air recently back over the mountains from where it came, forecasters said Friday.
A thermal trough centered over Puget Sound caused winds to flow from the east and south the past few days, siphoning smoke from fires raging in Eastern and Southwestern Washington into the South Sound.
That’s an unusual weather pattern for this time of year, said Erik Saganic, a weather forecaster for the Puget Sound Clean Air Agency.
Air quality crept Friday toward levels unhealthy for people sensitive to bad air and could remain near moderately unhealthy levels today, Saganic said.
But a weather system pushing in from the Pacific Ocean is expected to bring light to moderate winds from the west and north, blowing smoke-clogged air out of the area by this afternoon, Saganic said.
Winds from the north and west are expected to continue at least through Sunday, he said.
Wildfires had scorched more than 120,000 acres across Washington by week’s end, including 2,000 acres on the southern flanks of Mount Adams, the state Department of Natural Resources reported.
Ash from the Cascade Creek Fire on Mount Adams was reported falling as far west as Interstate 5, with smoke from that fire drifting into Thurston and southern Pierce counties, the National Forest Service reported.
Fire danger is rated as high for Pierce County and moderate for Thurston County heading into the weekend, and burn bans are in effect in both counties.