Saturday, September 15, 2012

Forecast offers some relief for E WA air quality, but ...

By Seth Preston, Communications Manager, Air Quality Program

The weekend weather outlook for Eastern Washington, from Ecology forecaster Ranil Dhammapala, offers some temporary relief for smoke-impaired air quality in embattled communities. The photo at right from a Forest Service camera reflects that.

But stagnant air conditions are expected during the coming week, which likely means a renewed build-up of smoke. Here's the forecast:

Air Quality forecast, 7AM Saturday 15 September
Issued by Ranil Dhammapala, Washington State Dept. of Ecology

Air quality still remains a concern through much of eastern Washington in spite of some limited clearing over the last 12 hours. Some gradual improvement is expected over the weekend.

The SW winds yesterday were weaker than expected but did help ventilate out the Palouse a little last afternoon. Some NW winds in Leavenworth, Ellensburg and the Methow last night, and in Wenatchee early today also helped lower the smoke levels. In general, expect the clearing trend to continue through Sunday evening, as winds pick up a little across most of the state.

However, during the process of clearing out, smoke from Washington wildfires is likely to periodically impact communities around the Columbia Basin as it is flushed out of the area through Sunday evening. Periodic smoke may also impact some communities in the northern counties and possibly the Spokane area.

After a dry cold front passes through on Saturday, smoke from Idaho wildfires is not expected to impact the Palouse or Clarkston over the next few days.

Alas, the clearing appears to be short lived. It is likely that air will stagnate throughout much of eastern Washington during the work week as strong high pressure builds over the area. Though pressure gradients do not go strongly offshore, it might be sufficient to push some smoke into western Washington. This bears watching and will be addressed in the next forecast issued on Sunday.

Please note that the Governor's Office has issued a burn ban in eastern Washington:

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