Smoky South Idaho

Air quality forecasts for today are in the Good to Very Unhealthy categories. 

Smoke is expect to shift east today and improve air quality across the southern Panhandle.  Impacts will still be prevalent in the vicinity of fires and downstream of active fires in other states, including in the Clearwater drainage and along the Canadian border.  Conditions look to deteriorate once more tonight and tomorrow before lifting in the afternoon over the Panhandle with general improvement over the Clearwater. This pattern continues on Sunday. 

South Idaho will see terrain-driven smoke impacts over the Middle and Upper Snake as northwest winds along a strong cold front bring smoke along parallel valleys (e.g. Pahsimeroi, Lemhi, Birch, Salmon, Big/Little Lost) beginning this afternoon by 3pm.  Expect surface smoke to remain across the elevated terrain of the Southeast, Eastern, and Southern Highlands. A southwest wind shift developing by 5pm Saturday will bring smoke from California to Southwest Idaho with smoke reaching the Owyhee’s by 11pm Saturday night. The highest concentrations look to bypass the Treasure Valley and instead reach the Magic Valley by 6am Sunday. Concentrations Sunday will be greatly influenced by the amount of sunlight reaching the surface and daytime heating.  If enough heating occurs, more smoke will be accessible to mix down to the surface.

Video: HRRR-Smoke Near Surface Smoke initialized at 12Z (06am MDT) and valid at 12Z (06am MDT) on 08/08/2021.  This shows ample smoke aloft over the Magic Valley with plenty of coverage over southern Idaho as well as the Panhandle.  How much smoke reaches the surface will depend on daytime heating.