Inversion Forecast

Update 01/26/2026: Overview: Persistent high pressure continues to frame the western U.S. with inversion-favorable ingredients, although the ridge itself is somewhat transient and the average weather pattern will see the ridge axis shuffle itself upstream and downstream. One caveat to this inversion tool under this particular type of pattern is the limited ability to capture short-term impacts as the ridge wobbles about. Generally speaking, the large scale conditions will see minimal amount of disruption to inversion-favorable ingredients. Short term: A shortwave ridge is predicted to strengthen through the early-week period with the axis of the ridge predicted to translate over the Utah region Tues-Wed. Inversions should take hold in valley locations as this ridge settles overhead, with air quality impacts following closely behind. On the backside of the quick-moving ridge will be a shortwave disturbance that, as of now, is predicted to translate through northern Utah Wednesday afternoon. Current forecasts show inversions mixing by Wed evening and remaining mixed during the Thursday heating. Beyond the midweek mixing, a broader, longer-lived ridge is forecast to build upstream. Inversions should return and have a greater potential for longevity through the end of the work week through the early week. Long term: While the dominant ridge pattern is well agreed upon by the buffet of extended range forecast models, there are several brief breakdowns that allow weak disturbances to filter through the region. While underwhelming precipitation outlooks remain, the potential for these disturbances to flip inverted valley airsheds should be a source of optimism during the bleak weather pattern outlook. However, the lead times of these disturbances are still far enough down range that caution wins over wishcasting. Such disturbance are notorious for their forecast challenges related to timing and track so we'll want to continue to see run-to-run consistency in the days leading up to these disturbances to feel more confident about their ability to disrupt inversions. Without these disturbances, the large-scale weather pattern is certainly going to present potential long-lived inversions. As has been the case this season, the lack of snow cover, and now, the increasingly longer days and higher sun angles should continue to help mitigate the macro-scale inversion ingredients.