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Oregon State Smoke Forecast for Thursday - Aug. 31, 2017 and into the Weekend

Issued:  Aug. 30, 2017
Forecaster.  R. Graw, USDA Forest Service

The upper level trough will move out of the state on Thursday, and a ridge of high pressure will begin to build in on Thursday and remain throughout the weekend. This will bring the return of hot, dry weather, and the associated increase in fire activity and smoke production. Assuming we don’t get any new fire starts, the smoke will continue to affect the areas which have been inundated with smoke already --  Southwestern Oregon, the Cascades, and the eastern slope of the Cascades from Klamath Falls north to Redmond. Other areas will be affected depending upon transport winds, as described below.

Thursday Aug. 31, 2017

A northeast wind will occur on the west side of the Cascades, which will keep smoke out of the Willamette Valley, and all but the southwest coast. The Columbia Gorge and Mountain Hood National Forest will also have good air quality. Unfortunately, the Rogue Valley is not likely to see a significant improvement in air quality, but could see periods of lighter smoke. Light northerly winds will occur in Eastern Oregon, which will likely experience some light smoke and haze, caused by smoke coming down from the fires in Central Washington. The areas of heavier smoke are shown in Figure 1 as indicated by the darker and medium shades of red in the Figure 1.

Figure 1.  Model-predicted 24-hour average smoke concentrations for Thursday Aug. 31, 2017

Friday - Sept. 1, 2017

Fire activity is expected to increase today with the return of hot and dry weather. Smoke will begin moving into the south and eastern portions of the Willamette Valley on Friday, but not affect the entire valley (that comes later in the weekend). The smoke from the Horse Prairie fire will affect the coastal areas southwest of this fire. Southwestern Oregon, including the Rogue Valley will be on the receiving end of smoke from the High Cascade Complex. The east side of the Cascades will experience an easterly wind pushing smoke from the Milli, Whitewater, and Falcon fires back towards the west, affecting mountain communities on the west side of the Cascades down to Eugene.  By afternoon the east wind in Central Oregon will bring hazy skies to nearly all of Western Oregon, and could mix down to the surface elevating smoke levels throughout the Willamette Valley.

Saturday - Sept. 2, 2017

Another hot and dry day is expected with elevated levels of fire activity. The day will begin with winds out of the east in western Oregon and out of the south and southeast for central and eastern Oregon. This will transport smoke into Western Oregon including the Willamette Valley and the Coast from the fires in the Cascades, but bring some relief to the communities on the eastern foothills of the Cascades such as Redmond and Bend. However, in the afternoon, a reversal of wind direction is expected, in western Oregon bringing some relief to the coast. These westerly winds will gradually extend across the Cascades and into central Oregon by early evening, bring the smoke back into the communities on the eastern foothills of the Cascades. Unfortunately, this will only bring some minor relief to the Willamette Valley and the wind speeds do not look very strong, and may not be sufficient to scour out the smoke.

Sunday - Sept. 3, 2017

The day will begin with light northerly winds in Western Oregon and westerly winds over central and eastern Oregon. Wind speeds will be increasing throughout the day, beginning in the Columbia River Gorge extending to Pendleton, followed by increasing westerly winds along the eastern foothills of the Cascades, by afternoon, and extending across much of the state, including western Oregon by early evening. This will likely help scour smoke out of areas many areas but also increase fire activity. Thus, the smoke should clear out of the Willamette Valley by night. Eastern Oregon will experience some light smoke and haze as the smoke from the fires in the Cascades in transported eastward. 

Please refer to the Air Resource Advisor Reports for more detailed forecasts associated with individual fires.  

Disclaimer: Weather and fire activity can change quickly. Please check back for updates to these forecasts as conditions change.