The sun will be shining on this year's Sundance Film Festival.

And the sunny weather forecast for the next week could draw crowds even larger than are typical for the festival.

Park City's weather is expected to be sunny through the festival, perhaps until the end of January. At the same time, an atmospheric phenomenon known as an inversion is anticipated to keep its grip on the Salt Lake Valley. In an inversion, the temperatures are\ colder at lower elevations and smog settles in.

Park City, at approximately 7,000 feet in elevation in Old Town, sits above the inversion that blankets the Salt Lake Valley. The temperatures could be a few degrees warmer in Park City than the Salt Lake area as well.

If the conditions hold, people who live in the Salt Lake Valley could head to Park City for a day of sunny skies over the weekend.

"It will be sunny and a little warmer," said Brian McInerney, a National Weather Service hydrologist who monitors weather patterns and lives in the Snyderville Basin.

An inversion traps the smog at lower elevations. Storms do away with inversions when they move in, but McInerney said none are forecast. He said the Salt Lake Valley is expected to have "patchy fog and haze."

The first weekend of Sundance is traditionally the busiest in Park City. Crowds from outside the state and the Salt Lake Valley descend on Park City on Friday, Saturday and Sunday for film screenings, celebrity gawking and partying. Main Street is especially busy, and traffic throughout Park City is some of the worst of the year.

Main Street is ready for the crowds, the leader of a group representing businesses on or close to the street said. Alison Butz, the executive director of the Historic Park City Alliance, recalled the terrible conditions -- rain, sleet and snow -- during the opening weekend of Sundance in 2012. Good weather like what is forecast is a draw, she said, adding that Monday's Martin Luther King Jr. Day could also lead to an increased number of people in Park City.

"The sidewalks are busy. The buses are full. There's a very good number of people out there," she said.