Inversion Forecast

Update 01/12/2026: Overview: A prolonged stretch of high pressure and stable conditions has already begun to entrench inversions across northern Utah with the expectation for these conditions persisting through the work week. Mixed agreement in the forecast weather pattern does offer the potential for slight improvements in the large-scale pattern arriving later in the week as a northern Rocky disturbance is forecast to translates through the region and displace the high pressure farther upstream. However, the rather unimpressive feature, as currently predicted, may not be sufficiently strong to erode inversions or may not evolve at all. Either way, the current thinking right now is for this week to see the year's most tangible inversion event play out across northern Utah valleys. Short term: High pressure remains in place across the western U.S., with the axis of the ridge and the most stable conditions predicted to remain just upstream of Utah. While that will drive stronger inversion conditions over the next few days than the year has seen so far, the lack of snow cover in most northern Utah valleys should help mitigate the worst scenario of impacts (Cache Valley excluded where snow cover persists). However, air quality is already trending into moderate categories and the expectation is for inversions to be sufficiently strong through mid week to yield unhealthy air quality levels through Thursday at the least. The potential for a weak system to translate through the northern Rockies later this week may help weaken the high pressure's grip on Utah's portion of the region, but without sufficient strength, it may offer little impact on entrenched inversion conditions. A reminder that this prediction tool will struggle to see the lack of influence by the disturbance and that the expectation is for inversions to remain to some degree. Long term: The extended forecast lynch pin relies on the upcoming weekend pattern, which still is uncertain to the degree and impact of a potential weak system to affect inverted valley air. Beyond this weekend potential, the over large-scale weather pattern is fairly uncertain and split across the collection of long-range forecast models. A much more active pattern and regional storm track is found in half the forecast scenarios, while the strong ridge of high pressure and inversion ingredients is found in the other half. Even the placement of the axis of low pressure and high pressure features is mixed, suggesting that little confidence can be found in the large-scale weather patterns beyond this weekend.