 |
| The Air Quality Index at 10 a.m. See the map above for current conditions. |
Forecast Issued: Tuesday July 31, 2018
Forecaster: James Miller, USDA Forest Service
At 11 a.m. on Tuesday, July 31,
moderate air quality prevailed across Eastern Oregon. An upper-level high
pressure ridge centered over Eastern Washington and Eastern Oregon will produce another
hot day east of the Cascades with daytime temperatures running 10 to 20 degrees Fahrenheit above average with hazy skies and moderate air quality expected to remain over
the region for most of the daylight hours on Tuesday.
Over the next 24 hours,
the ridge will move eastward as an upper-level trough approaches the Pacific
Northwest coast. This will result in gusty southwesterly to westerly winds that
should provide some improvement in air quality across Eastern Oregon, possibly
returning to good air quality conditions in the Grande Ronde Valley by later
this evening and early Wednesday morning.
 |
| Near-surface smoke forecast from the High-Resolution Rapid Refresh Model. |
However,
both the AIRPACT 5 and High-Resolution Rapid Refresh smoke models suggest strong southwesterly winds
aloft on Wednesday afternoon will transport smoke from Northern California and Southern Oregon to much of Southeastern Oregon, particularly south of Baker
City where air quality could degrade to unhealthy for sensitive groups.
Notably, both the AIRPACT 5 and High-Resolution Rapid Refresh models forecast a
sharp transition between relatively good and degraded air quality on a
southwest-to-northeast line from roughly Klamath Falls to Baker City. North of
this boundary, good air quality should occur by late afternoon Wednesday,
while air quality south of this line may deteriorate. Given the sharp near-surface
smoke transition depicted by the models, small shifts in the forecast could
result in more widespread air quality impacts on Wednesday afternoon into
northeastern Oregon, including the Grand Ronde Valley.
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.