GOES West “true-color” visible satellite imagery from 7:51-9:16 AM MDT showing the sun rise illuminating numerous wildfire plumes and trapped smoke in canyons and valleys across Idaho. Smoke from the fires in the Cascade Range is moving east across Oregon.
Friday, September 11, 2020
Smoke is coming!
Air quality yesterday was good to moderate across the state with one monitor in Orofino in the unhealthy category. That monitor is in the hazardous category this morning while everywhere else remains good to moderate. Air quality is currently forecast to be in the good to moderate range but this may change as conditions deteriorate through the weekend.
Westerly flow is returning and will push smoke from the numerous large fires in the Cascade Range east into Idaho beginning Friday afternoon. Periods of stagnant conditions, particularly on Saturday, will allow much of this smoke to linger at least through Sunday. Significant relief is not expected until at least Monday or Tuesday.
The heaviest smoke is expected to begin arriving Friday evening and continue through Saturday night with nearly all areas seeing moderate to heavy impacts. The exception will be eastern and southeastern Idaho which may avoid the worst impacts but will certainly see some amount of smoke move in. The shift to southwesterly winds on Sunday may provide some relief to southwestern Idaho but will ultimately bring in more smoke from the fires burning in California. It can be expected that north, central, and southwest Idaho will see periods of widespread air quality degradation beginning Friday evening and continuing through at least Monday. Air quality will likely worsen overnight as the smoke settles down into the valleys and canyons and then improve slightly each afternoon as the atmosphere warms.