Strong Temperature Inversions and High Pressure with Little Snow for the Next Week
High pressure has become well established over much of the Western U.S. and will dominate through the coming weekend. The storm track has shifted well to the north of Star Valley resulting in a rather stagnant weather pattern. Strong inversions have developed in Star Valley under the generally clear and calm conditions and only limited daytime heating this time of year. The results are that the coldest daytime temperatures are occurring on the valley floor with considerably warmer readings above the inversion in the higher elevations. As an example while the afternoon temperature in Afton was only able to rise to 10 above Thursday, after a morning low of -9, it warmed to near freezing at Salt River Summit at an elevation some 1500 feet above the valley floor after a morning low of plus 7.
Visual evidence of this strong temperature inversion can be seen, particularly around Afton at the top of the haze/smoke layer.
Once these inversions become established this time of year, they will require a breakdown of the current high pressure to increase the atmospheric mixing to remove them. The earliest this seems likely to occur will be early next week when a weakening upper trough of low pressure is forecasted to cross the area. Until then expect plentiful daytime sunshine, but continued cold conditions in the Valley. Warmer conditions will continue to be observed in higher elevations where in some cases the morning lows will be higher than the adjacent valley afternoon highs.
Snow flurries are likely this Wednesday night as a weak disturbance passes across the area, however no accumulation is expected. The next chance of any significant snow appears to be no sooner than the middle of next week.