There have been wildfires, heat and haze before in the Pacific Northwest.
But nobody can remember ash falling on the Seattle area like it has been this week. Even when Mount St. Helens blew, say people who lived here in 1980, Seattle didn’t get any ash because wind blew to the south and east.
“Basically, it was a perfect storm of conditions coming together to bring the ash our direction,” said Dustin Guy, a meteorologist with the National Weather Service in Seattle. “It was a combination of the closer proximity of the fires in the Cascades and to the south in Oregon, and the offshore winds which helped the fires grow in size and blew the ash here.”
When Seattle got smoke and haze from the wildfires in British Columbia last month, they were farther away and the ash had some time and distance to disperse, Guy said.
Monday bye bye mountain. Tuesday almost bye bye Mercer Island. Smokey conditions improving tonight on the Coast, interior on Wednesday. #wawxpic.twitter.com/OomsDuV8J0
— NWS Seattle (@NWSSeattle) September 6, 2017
The rare phenomenon will be gone by Thursday, when a weak weather system blows in north of Seattle, bringing slightly cooler air and a chance of showers, according to the weather service.
“Right now, the smoke layer is over us, but we’ll see a slow improvement this afternoon,” said meteorologist Dana Felton on Wednesday, “and it will be out of here tomorrow.”
Felton also said the system will bring two layers of marginally cooler air and cloud cover that will slowly begin to cool the air through Saturday, with highs on Wednesday and Thursday that will reach in the lower 80s. A second weak system will come in on Saturday, also bringing a chance of rain and continued cooler temperatures, he said.
“The winds have shifted at the surface and aloft from easterly to more westerly,” said Felton. “That will stop the smoke from dumping into the area and eventually will push it out of the area.”
“The air quality will improve but we will still not see a lot of sunshine,” Felton said.
He said any rain as a result of the weak weather systems will be light.
On Sunday, things will begin to warm up again as another ridge of high pressure builds. It will not bring the scorching heat of last month but instead top out around 80 degrees, he said.
Felton said Seattle-area residents can’t rule out super hot days yet, though.
“It’s been a year of extremes,” he said. “We’ve never had five consecutive days with highs over 85 in the month of September in all of the 120 years of record keeping. We have certainly had our share of extremes from the wettest to the driest to the hottest. We’ve broken all the records.”
