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- Utah's Wasatch Front continues to face poor air quality due to a temperature inversion.
- Air quality is expected to improve by the end of the weekend as a cold front arrives.
- Future storms are possible in the long-range forecast, which may prevent prolonged inversions from forming.
SALT LAKE CITY — Utah continues to have some of the worst air quality in the U.S. amid the latest temperature inversion impacting the Wasatch Front, which began shortly after Thanksgiving.
Inversions form when cold air sinks into the valley and warm air moves on top of it while high pressure builds up in the area. It essentially creates a lid that traps pollution in the air, producing a haze that can last a few days or weeks, as what happened at least once in the 1980s.
In this case, air quality across the Wasatch Front ranged from moderate to unhealthy for sensitive groups to unhealthy for everyone yet again on Thursday, according to the KSL Air Quality Network. With an air quality score of 124, IQAir listed Salt Lake City as having the 22nd worst air quality in the world Thursday afternoon, and the worst in the U.S. among the bigger cities it tracked.
Dense fog emerged near the Great Salt Lake later in the day, reducing visibility further.
Kaysville topped the list Thursday morning for most polluted city, along with Midvale, South Jordan and Saratoga Springs in the top 10. Factors such as lower elevation, stagnant air, being close to freeways or either emission sources and time of day all contribute to a city's concentration of pollutants and air quality.
They were knocked off IQAir's rankings by cities across California dealing with their own inversion issues, according to Los Angeles Magazine.
However, relief appears to be on the way for the Wasatch Front.
Utah's poor air quality is expected to linger through at least the start of this weekend, but KSL meteorologist Devan Masciulli said the core of the high-pressure system currently over Utah is drifting southwest, allowing a cold front to sweep through the region either Saturday or Sunday.
Inversions will remain in place for the valleys of northern Utah until Saturday, with improvement by Sunday. This will result in a continued decline in air quality, particularly impacting sensitive groups. #utwxpic.twitter.com/3Hi4ECfwIj
— NWS Salt Lake City (@NWSSaltLakeCity) December 6, 2024
The cold front is tied to a storm coming in from the Pacific Northwest. It's not expected to produce that much moisture, aside from a possible brushing of snow, but it should be cold enough to improve air quality toward the end of the weekend.
"It will pass through dry, but what it will do is bring colder air aloft. So, that will actually help release that lid that we have in our atmosphere right now," Masciulli said. "It'll slowly take that lid off; we'll see the haze in the valley mix away, and that will bring us much better air quality as we head into Monday."
Meteorologists had hoped that another system in the West would have broken up the inversion on Friday, but Masciulli said the cold front ended up moving too far north and east to make any sort of difference.
Meanwhile, there's growing hope that more storms are headed Utah's way. The National Weather Service's Climate Prediction Center lists Utah as having a greater probability for above-normal moisture between Dec. 13-19 in an updated outlook released on Thursday.
An active pattern would prevent future inversions from lasting long, which is good for the region's air quality.
Full seven-day forecasts for areas across Utah can be found online, at the KSL Weather Center.
Contributing: Shelby Lofton
