|Sounding source: SPC|
|Source: Pataki et al. (2005)|
As a result, our pollution is mixing through a layer that is about 850 meters (2775 feet) deep, which is right up to the base of the inversion. That's much better than when the inversion is based very near the valley floor.
The development of this cloud topped mixed layer is one reason why PM2.5 levels have remained at moderate levels the last two days. Basically we are seeing pollution dilution due to its development.
|Source: Utah Division of Air Quality|
All else being equal, a cloud-topped mixed layer with a deep cold pool and elevated inversion results in lower PM2.5 levels on the valley floor than a shallow cold pool with a near-surface inversion. On the other hand, if the benches or perhaps places like Emigration Canyon see higher PM2.5 levels.
Looking toward the future, the overnight model runs are showing a vigorous trough passage tomorrow (Wednesday) that should crack this inversion. Although quick hitting, the system will generate snow down to the valley floor. Students with finals tomorrow should consult National Weather Service Forecasts and plan on leaving early. No excuses! The official forecasts of 6-12" in the mountains are looking pretty good. Pro Tip: Lift-served skiing tomorrow will be better late than early.