SALT LAKE CITY — Cities across the U.S. are bracing for cold temperatures as a polar vortex arrives, bringing temperatures down to much below normal for mid-to-late January.

Parts of Utah are on the "very western fringe" of a cold front that will bring in air from the Arctic. This front will likely create the coldest temperatures the state has seen so far this winter, but KSL meteorologist Matt Johnson says what's expected in Utah is nothing like what will be experienced elsewhere in the country.

The cold front will also bring more snow to parts of Utah and clear out the latest inversion.

Cold air arrives

Polar vortexes happen when low pressure and cold air near the North Pole move toward the contiguous U.S., as noted by the National Weather Service. Utah is usually protected from these vortexes because the cold, dense air struggles to move over the Rocky Mountains and other areas west of the Continental Divide. However, Johnson said Utah is on the tail end of the cold front this time around.

The polar vortex is expected to reach the Utah-Idaho border sometime in the late afternoon and evening Friday as it continues to move south. As it moves through parts of the state, it will produce small snow showers, bringing more snow to the region before drier conditions return.

The storm isn't expected to produce much in terms of moisture. A trace to an inch of snow is forecast for most communities along the Wasatch Front and northern Utah, while mountain areas could receive up to about 6 inches of new snow.

The bigger impact will be the cold temperatures, especially since it has been a mostly mild winter for the state. Johnson explains trailing shortwaves from the Arctic will continue to push cold air into the region behind the cold front, keeping temperatures down.

"A lot of time when you have that initial front, you'll have bits and pieces — waves of energy — that follow within the jet stream that can reinforce your cold air," he said, adding a jolt of "extra dry" and cold air is expected to arrive by Monday.

High temperatures across the Wasatch Front and Tooele Valley are forecast to drop from the upper 30s and low 40s on Friday to the upper 20s and low 30s through the weekend and into the start of next week. Overnight lows are forecast to drop into the teens over that time.

That's a big change because Salt Lake City's coldest high temperature since November is 36 degrees Fahrenheit, while overnight lows haven't dropped below 21 degrees.

Logan may only top out in the low 20s on Monday, and overnight temperatures are forecast to drop into the single digits. Vernal's high temperatures will drop into the mid-20s, and overnight lows could drop below 0 degrees.

Bracing for impacts

The Utah Department of Health and Human Services notes Code Blue conditions were already in place for most of the state ahead of the cold front, enacting emergency homeless shelter measures. Those conditions are expected to last through at least the first half of next week.

Rocky Mountain Power officials also emailed customers about the forecast Friday morning, advising them that "colder than normal winter weather" is expected within its service area that could create "higher than normal energy usage."

The company recommends people set their thermostat at 68 degrees when they're at home and lower by "several degrees" when away or at bedtime. It also recommends that people close drapes or blinds at night to help keep heat and recommends against using any portable space heaters and limiting appliances like ovens, dishwashers and clothes dryers during overnight hours.

Southern Utah communities aren't expected to be as impacted by the cold. High temperatures will drop from the upper 40s and low 50s to the upper 30s and low 40s in the St. George and Cedar City areas over the weekend.

Utah will also be spared the brunt of the cold because of the Continental Divide, Johnson added. Much colder temperatures are expected in the Midwest and eastern U.S, where high temperatures in cities like Chicago will drop from the 40s on Friday to single digits by early next week — with even lower wind chills.

President-elect Donald Trump will be inaugurated indoors on Monday because of the cold temperatures forecast for Washington, D.C.

Cold to continue?

While temperatures may increase slightly later next week, long-range forecasts indicate another blast of cold air is possible late next week. Johnson said some models indicate it would produce similar temperatures to those expected in the next few days.

However, he said not every model has indicated Utah will receive a "direct hit" of cold air with that storm. It's something that will become clearer later in the week.

Full seven-day forecasts for areas across Utah can be found online, at the KSL Weather Center.

Weather the storm:

KSL Weather Center

Looking for detailed weather information in your area? See the full seven-day forecast and KSL Vortex radar maps for areas across Utah by visiting the KSL Weather Center.

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