|The Wasatch Range from Neil Armstrong Academy (West Valley City). Courtesy MesoWest.|
I'm not sure where the smoke is coming from, but yesterday we had a very weak trough passage, resulting in a brief period of northwesterly flow at 700-mb, as indicated in the analysis below for 6 PM (0000 UTC).
NASA Worldview imagery from yesterday shows smoke across much of the Intermountain West, but the greatest concentrations were over northwest Nevada and southern Idaho, so perhaps that northwesterly flow brought in some of that smoke.
So far this fire season I think northern Utah has been quite fortunate. We've had some incidents (e.g., Antelope Island), but for the most part it's been pretty quiet considering that the landscape is a tinderbox right now. Hiking and biking the past couple of weeks I've noticed that not only the grass is dry, which is pretty typical for late summer, but even many of the trees, shrubs, and vegetation is looking pretty brown. Low areas and seeps that often stay green through the summer look quite stressed and dry as well. Let's hope we make it to the snows of fall without major incidents.