Maybe you're new around here or need a refresher: what is an inversion? Simply put, an inversion is a layer of the atmosphere in which air temperature increases with height. The warm air aloft acts as a "cap," trapping cold air and pollutants below it. Valley inversions persist today, though cooler air moving in aloft allowed the inversion to weaken slightly. Expect inversion conditions to linger this weekend into early next week, with patchy fog developing in the vicinity of the Great Salt Lake each morning.