|Dude, I can barely see the Oquirrhs!|
As everyone is aware, late last week and last weekend and deep upper-level trough and associated cold-air intrusion rumbled through Utah. The maximum temperature on Friday was only 51ºF.
As the trough moved downstream, a high-amplitude upper-level ridge built rapidly over the western United States. This led to significant warming in the mid- and upper-levels of the atmosphere at a rate faster than solar heating could warm the colder air near the surface.
As a result, yesterday afternoon, the atmosphere over the Salt Lake Valley was capped by a series of stable layers. The lowest of these stable layers was only a few hundred meters above the valley floor.
|Source: Storm Prediction Center|
Such conditions are a bit unusual for September, but there are probably three issues at play. The first is the depth of the weekend trough and strength of the cold air, followed by the building of a strong ridge and associated rapid warming aloft. Second, we received a great deal of rain Friday and Saturday, leading to high soil moistures. As a result, a portion of the sun's energy that often would be partitioned into heating the ground and atmosphere is being used for evaporation and transpiration. Finally, we simply have to realize that we have more people living here and driving farther than every before. I suppose there might also be some smoke sources out there, although I'm unaware of any major incidents in the immediate area.