Forecast Issued: Nov. 16, 2018
Forecaster: James Miller, USDA Forest Service
Forecaster: James Miller, USDA Forest Service
Overall,
air quality across Oregon has either improved slightly or remained unchanged
compared to yesterday morning. Locations in the Portland to Eugene corridor
have experienced slight improvement, but still remain in the moderate air
quality category. The most improvement has been within the Portland metro area,
where several locations experienced unhealthy for sensitive groups air quality
yesterday morning whereas good to moderate conditions were in place this
morning.
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| Figure 1. The Air Quality Index at 8 a.m. on Friday, November 16, 2018. |
For
the rest of today, favorable low-level winds and upper-level atmospheric conditions
from a passing weak-weather disturbance should lead to continued air quality
improvement in the Willamette Valley, with good to moderate air quality
expected in more locations by tomorrow.
Improved
atmospheric mixing will also likely produce slight air quality improvement for
most of the state by tomorrow, but high-pressure generally remains in place
over the region through early next week, so air quality improvements may be
short-lived, especially in Central and Southern Oregon. As a result, the Oregon
Department of Environmental Quality extended an air stagnation advisory for Southern Oregon through Tuesday in addition to issuing a new advisory for Central Oregon that will be in place from Sunday through Wednesday.
Mid
to upper level winds may also introduce smoke from California wildfires into
southern portions of the state early next week. The return to weak low-level
winds in central and Southern Oregon following a brief improvement in
atmospheric mixing this afternoon through tomorrow will trap wood stove and
wildfire smoke within valley locations.
However,
at this time, we do not expect California wildfire smoke to impact Northern
Oregon early next week, so air quality in the good to no worse than the moderate
category is anticipated through midweek in the Willamette Valley.
Widespread
good air quality should prevail by Thanksgiving into the post-holiday weekend as
a more progressive weather pattern develops, bringing a chance of rain and
mountain snow for most of the state.
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Figure 2. Near-surface smoke
forecast from the AIRPACT-5 model for Friday, Nov. 16, 2018 at 6 p.m.
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Figure 3. Near-surface smoke
forecast from the AIRPACT-5 model for Saturday, Nov. 17, 2018 at noon.
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