Forecasters here are monitoring smoke from California that has the potential to reach Western Washington this week. Easterly winds have revved up and the smoke is accumulating offshore. Some of it is expected to flow north, but how much, exactly when and how it impacts air quality once it arrives are all open questions at this point.
Forecasting smoke is a lot harder than predicting the weather that could carry it into the region. Most of the time, a 10-day forecast is accurate enough to reliably predict conditions and plan outdoor activities. But atmospheric scientists say they only have confidence about two days out when looking at air quality that’s impacted by distant fires.
“Because you don't know if they'll be new fires or if the firefighters would be able to get an upper hand on some of the fires they're already dealing with. Or if some smoke, some wind could kick up more smoke and essentially fan the flames of existing fires,” said Ranil Dhammapala. He’s the lead smoke forecaster at the state Department of Ecology.
Added to that is the question of how high into the atmosphere the smoke will go if new smoke is generated, and whether it will mix back down to the surface.
“Because at certain heights, you know, it might not mixdown back to the surface and it might not be much of a public health issue,” Dhammapala said.
Where the smoke lands determines whether people should stay inside or if it just causes some colorful sunsets, he says.
As for this week, all of those questions are open for debate right now, although authorities have said they think this next event probably wouldn’t last more than two or three days, if it does materialize.
Smoke forecasters from the state Department of Ecology will take part in a conference call with the National Weather Service on Tuesday morning, after which they hope to have a clearer picture of what the public should expect.