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| The Air Quality Index at 9 a.m. on Tuesday, Aug. 21, 2018. See the map above for current conditions. |
Forecast
Issued: Aug. 21, 2018
Forecaster: James Miller, USDA Forest Service
Forecaster: James Miller, USDA Forest Service
As of 10 a.m. on Tuesday, Aug. 21, 2018, all
air quality monitors in the Oregon were reporting air quality indices in the
moderate or worse category. Unhealthy conditions prevailed from Portland to
Salem while further south in the Willamette Valley, unhealthy for sensitive
groups air quality was observed in the Eugene metro area. Compared to yesterday
morning, conditions have improved in Northeastern Oregon where generally
moderate to unhealthy for sensitive groups air quality was reported during the
late morning hours on Tuesday. In Central and Southern Oregon, including
Ashland, Bend, Klamath Falls, Lakeview and Medford, unhealthy air quality
indices were observed Tuesday morning.
For the remainder of Tuesday, there are no major
changes to the forecast made yesterday. Throughout the state, air quality will
remain degraded on Tuesday from fires burning to our north in British Columbia
and Washington, and from those in Southern Oregon. The latest High-Resolution
Rapid Refresh Model indicates there should be some air quality improvement on
Tuesday afternoon for Northeastern Oregon and possibly Northern Oregon west of
the Cascades, though much of this depends on fire behavior to the north in
Washington. However, it does appear that smoke levels have decreased somewhat
in parts of Northern Oregon as seen in the late morning web cam images from the
U.S. Forest Service’s Columbia Gorge (CORI1) and Mount Hood (MOHO2) IMPROVE air
quality monitoring locations. While still very hazy at both locations,
conditions are better than 24 hours ago (see yesterday’s statewide forecast for
a comparison). Unfortunately, conditions in Central and Southern Oregon are not
expected to improve Tuesday.
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| View west from the Columbia Gorge IMPROVE air quality monitor near Wishram, WA at 10:45 a.m. on Tuesday, August 21, 2018. See current image. |
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| View south from the Mount Hood IMPROVE air quality monitor near Government Camp, OR at 10:45 a.m. on Tuesday, Aug. 21, 2018. See current image. |
Late on Tuesday and into Wednesday, air
quality should begin to improve for the northern half of the state, especially
east of the Cascades. However, west of the Cascades in the Willamette Valley,
the High-Resolution Rapid Refresh Model suggests that smoke currently over
Western Washington will move into Northwestern Oregon, affecting coastal
communities as well as the central and northern Willamette Valley. This smoke
over Northwestern Oregon should begin to push eastward by midday on Wednesday,
but air quality impacts will likely remain until late into the day on Wednesday
for Northwestern Oregon. Much improved conditions are expected over the
majority of Northern Oregon on Thursday when a strong marine push brings
westerly winds that should effectively scour out the remaining smoke over the
northern zones.
For Central and Southern Oregon, there may be
some air quality improvement on Wednesday, but currently the forecast still
indicates that smoky conditions will prevail over the central and southern
coastal zones, the Southern Willamette Valley (e.g. Eugene), and the major
cities of Southern Oregon. As has been the case for several weeks now, Ashland,
Klamath Falls, Lakeview, and Medford will experience heavy smoke levels leading
to air quality indices likely in the unhealthy for sensitive groups or worse
category throughout the day Wednesday, with localized unhealthy to hazardous
conditions possible near wildfires burning in the region.
Overall, residents and visitors to the state
of Oregon should expect major air quality impacts to continue throughout
Tuesday, with some potential improvement on Wednesday, especially in the north.
By Thursday, conditions are expected to improve considerably for a large portion
of the state as a major weather pattern shift occurs that should lower temperatures
to slightly below seasonal averages under westerly to northwesterly flow.
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| Near-surface smoke forecast from the High-Resolution Rapid Refresh (HRRR) Model for Tuesday, Aug. 21, 2018 at 4 p.m. (top) and Wednesday, Aug. 22, 2018 at 4 p.m. (bottom). |
Disclaimer: Forecasting weather, fire behavior, and smoke transport and dispersion is challenging. While we strive to bring you the most up-to-date and accurate forecasts, conditions can and do change rapidly. Please take the appropriate action to protect yourself.