Issued: Sept. 1, 2017
Forecaster. R. Graw, USDA
Forest Service
Saturday - September 2, 2017
Very hot and dry weather is expected as a thermal ridge moves
into the state. This will continue to
dry out fuels and cause increase fire activity with the associated instability,
thus causing more smoke. East winds will
occur in western Oregon bringing smoke from the Cascades all the way to the
coast, as illustrated in Figure 1 below. The entire Willamette Valley will see some smoke, with the heaviest
concentrations in the southern portion of the Valley. However, Central and Eastern Oregon will be relatively
smoke free except for some possible light smoke or haze moving in from Idaho
and Washington. Klamath Falls may get
some light smoke as well from the Jade Creek fire near Lakeview.
Figure 1.
Model-predicted 24-hour average smoke concentrations for Saturday
Sept. 2, 2017
Football Forecast: Saturday afternoon, September 2, 2017
OSU vs PSU: Reeser
Stadium, Corvallis - kick off at 11 am
Figure 2 illustrates the model-predicted smoke concentrations
between 11 a.m. and 2 p.m. tomorrow. Note,
the model is likely under predicting the
amount of smoke likely to occur because it uses yesterday’s smoke emissions and
assumes these will persist through the forecast period, whereas fire activity
is expected to increase today and tomorrow compared to yesterday. Nonetheless, the overall spatial pattern is
and relative amount of smoke is still valid. Thus, smoke will likely be present in moderate to unhealthy concentrations
in Corvallis tomorrow during the football game.
Figure 2. Model-predicted three-hour average smoke concentration from 11 a.m. - 2 p.m., Saturday Sept. 2, 2017
OU vs S. Utah: Autzen
Stadium, Eugene - kick off at 5:15 pm:
Air quality should improve for the University of Oregon game, as
illustrated in Figure 3 below. Much of the
smoke in the Willamette Valley is expected to disperse yielding clearer air for
the Ducks game.
Figure 3.
Model-Predicted Smoke Concentrations for the 3-Hour Period ending at 8
p.m. on Saturday Sept. 2.
Sunday - September 3, 2017
Smoke will begin to lift and move eastward on Sunday. This will help clear out any remaining smoke
on the Coast in the Willamette Valley. Brookings and Gold Beach will get some
relief from the smoke in the afternoon, but not to area from Roseburg south to
the Rogue Valley as the Miller Complex and Chetco Bar and Horse Prairie fires
will continue to cause air quality issues for these areas. The winds will push the smoke into Central Oregon impacting Sisters, Bend, Klamath Falls, and surrounding communities. Eastern Oregon will likely see some haze
caused by the fires in the Cascades and some light smoke at the surface as
afternoon mixing brings this smoke down to the surface. Figure 4 illustrates the overall pattern and
relative concentrations of smoke for Sunday. However, the concentrations are likely underestimated for reasons
previously discussed in this forecast.
Figure 4.
Model-Predicted 24-Hour Smoke Concentrations for Sunday, Sept. 3, 2017
Monday - September 4, 2017
A ridge of high pressure will remain over the state on Monday,
as hot temperatures continue over the holiday weekend. For the western portion of the state, winds
will be out of the north all day, bringing good air quality over the coast and
Willamette Valley throughout the day. The areas from Eugene south to the Roseburg, will experience winds which
will begin from the northeast but shift to the northwest throughout the day. Thus, any smoke
that may begin in this areas should move out throughout the day. The Siskiyou Mountains will also experience a
wind shift from an east wind in the morning to a west wind in the afternoon and
evening. Because the area is surrounded by fires on all sides, it is expected to remain smoky throughout the
day. Central and Eastern Oregon are likely
to get a break from the smoke on Monday as east winds are expected all day.
Please refer to the Air Resource Advisor Reports on this blog 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. If
you’re traveling out of Oregon, many other states also have smoke blogs,
including California, Washington and Idaho. So please consider those resources
to help you plan your travels.