For Loop

Clear skies with lows in the 20s F this morning across the Wasatch Front valleys, with some high level clouds and temps maxing out in the 40s F this afternoon. Feels a little familiar... 

We've been stuck in a loop across northern Utah and we need a break. Everyday for the past 5-7 days has had pretty much the same weather and periods of poor air quality. This pattern will continue for the next two days, so a little bit of a broken record but persistence forecasting does work well in this situation. 

KSLC 2m Temperature (F) 1/15-1/21/2026

What's the reason for the weather on repeat and bad air? 

Utah has been stuck on the downstream periphery of a large and stubborn upper-level ridge for the last 10 days or so. It's a frustrating position to be in, with the storm track to our east and high and dry conditions overhead. However, being on the edge of the ridge does give Utah some fringe benefits. Energy diving south on the backside of the ridge can graze the state and keep the mid-levels of the atmosphere fresh enough to weaken our valley inversions. Thankfully, this has been the case, with air quality improving over this past weekend as a few shortwave troughs clipped the state. The glancing blows from the troughs brought the addition of cooler mid-level temperatures and some elevated mid-level winds that helped vent/mix-out the valley at times. 

Hourly PM2.5 concentrations (umg/m3) 1/15-1/21/2026 at Hawthorne and Copperview air monitoring station

Keep an eye on the blue dashed lines (representing 700 mb temps < 0 C) in the animation below from 1/15-1/20/2026 and note how the isotherms change through time over Utah. Pockets of colder temperatures are associated with the shortwave troughs progressing through the flow. From 1/15 to 1/17/2026, 700 mb temps decreased from +4 C to -4 C, respectively. This cooling is also noted in the KSLC soundings shown below from these dates. Even what seems like a subtle changes - a delta of a handful of degrees C - can weaken inversion conditions and "lift the cap/lid", allowing air trapped in the valleys to release. 

700 mb Analysis heights, temperature (C), and winds 1/15-1/20/2026

When will the loop break?

Going through the end of this workweek and into the weekend there is both good and bad news. The good news is that a trough and attendant cold front will dive south out of Canada and progress across Utah 1/23-1/24/2026. There is still some uncertainty on how far the trough will dig into Utah, but the upper-level energy and influx of colder air will help sweep out the valley and inversions for good - at least for a short time - and bring some colder temps. Maybe even bring our temps back near normal. But - and here is the bad news - moisture will be lacking as this system passes over northern Utah and no significant precipitation looks impact the area. Southern Utah does look to squeeze out some rain/snow showers as a southern tracking system merges with the trough out of Canada, but even there the precip amounts look fairly light. 

ECMWF 12Z 1/21/2026 four-panel forecast 1/21-1/25/2026: (Top left to bottom right) MSLP/precip and 1000-500 mb thickness; 300 mb gph and winds; ; 500 mb gph, vorticity, and winds; 700 mb gph, RH, temp, and winds

So... unfortunately, no new snow is in the forecast for northern Utah going through this weekend. Beyond that, the pattern looks to return to something along the lines of what we are experiencing currently, which is dry and somewhat mild. That's not exactly hopeful news, but things can always change. I think Utahn's and people across the western U.S. are searching for a light at the end of the dark tunnel that has been this winter. However, I don't see that light just yet... I will leave you with the image below.

Basin Snow Water Equivalent Percent of 1991-2020 median 1/20/2026