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A series of storm systems expected to pass through northern Utah this week probably won't be strong enough to completely clear valley air. But if an inversion does develop, it shouldn't be as severe as last week, when several communities registered the most polluted air in the country.

The National Weather Service is calling for a 30 percent chance of snow through much of the state Wednesday through Saturday. In Salt Lake, Tooele and Utah county valleys, there's a 60 percent chance of snow on Thursday, falling to 40 percent on Friday.

But snow accumulation from the storms, which began Monday morning during the commute, will be light.

"We might get a little snow," said Mike Conger, a forecaster with the National Weather Service's Salt Lake City office. "It may never clear out the bad air, but it could be a little better. Things should work out better for Cache Valley and from the Ogden area north."

On Friday, Logan, Provo, Ogden and Salt Lake City had some of the worst air in the U.S., according to Air Now, a national cooperative of government agencies that monitors PM 2.5, a soup of microscopic particles of soot and chemical pollutants, and other measures of air quality.

Air quality was listed as good Monday for all Wasatch Front counties except Cache, which was moderate, according to the Utah Division of Air Quality. By Wednesday, the division is predicting an air alert in Cache, where sensitive people should reduce outdoor exertion. The forecast for all other counties is moderate by Wednesday.

Monday's early storm slowed traffic as roads became slick. A Utah Highway Patrol trooper suffered minor injuries when his cruiser was hit on a snowy stretch of Interstate 15. The trooper was sitting inside his parked car near Brigham City, writing an accident report, when a car going too fast for conditions crashed into an arriving tow truck, pushing it into the cruiser, the UHP said.

No one else was injured in the 5 a.m. crash.

A couple of Utah communities posted record low temperatures on Monday.

Randolph recorded a record low of minus 24, breaking the record of minus 22 set in 1987. Cedar City's mark of minus 6 broke the mark of minus 2 set in 1949.

Lois McLean of Gator's Drive-In in Randolph said that while a few folks still request shakes and ice cream cones, the little restaurant will wait until spring before running its ice cream machine.

"We're freezing," she said. "Cars won't start. When it gets down to 25 or 30 below, we stay in and we're not in the cold very much. A lot of people have car batteries they can plug in or keep their vehicles in garages. Others go out and start them once or twice a night."

Conger said temperatures should move closer to normal by Friday. In Salt Lake City, the high should be around 35 degrees, while St. George will be around 51.

"The farther south you go, the drier it will be," he said. "We will get warmer temperatures midweek."