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Elijah Duckels passes through the frost-covered landscape Tuesday afternoon on a stroll through Silver Park near the Clark Fork River. The dense, stagnant air causing the accumulation of hoarfrost is forecast to continue until Friday.

LeeAnn Allegretto is trying her best.

“I’ve been casting my line out to reel in this system next week, so cross your fingers,” the meteorologist for the National Weather Service in Missoula joked Tuesday.

All indications are that the dense, stagnant air blanketing river valleys in western Montana since early December will be replaced by a moist system starting Friday. The cold front should produce snow that sticks, Allegretto said — “not a lot, but more than we’ve seen recently.”

But behind that, starting Sunday, there’s an active, moist pattern on the way that’ll last through next week.

“The thing that has me excited is, along about the 20th, all forecast models point to a significant storm that’ll put inches (of snow) on the valley floor,” Allegretto said. “That’s still a week or more away, but I’m holding on to that.”

The prospect of popping out of the gloomy inversion is good news at Missoula International Airport, where forecast freezing fog scuttled two commercial airline arrivals Monday night.

Brian Ellestad, assistant airport director, said an Alaska flight from Seattle and the last of three Delta flights from Salt Lake City were scuttled.

They were the first two fog-caused cancellations of the inversion. Fog seeding, which is effective only when the temperature dips below 28 degrees, has been taking place off and on throughout the week, Ellestad said.

Delta added a flight Tuesday morning for passengers from Salt Lake who didn’t make it in late Monday, a flight that normally lands shortly after midnight. It arrived at 10:30 a.m.

“We’re above landing minimums right now, so the planes are coming and going,” Ellestad said Tuesday morning. 

As a rule of thumb, a cloud ceiling of at least 200 feet and visibility of half a mile are required to land in Missoula, though those parameters vary depending on the type of aircraft involved.

An early Delta flight to Minneapolis, which normally departs at 5:24 a.m., was delayed Tuesday until 1:40 p.m., but Ellestad said that was due to mechanical issues, not the fog.

Climatologists as late as Nov. 16 predicted above-average precipitation this winter throughout Montana. But the Missoula Valley hasn’t seen snow that stuck since Nov. 17. The inch and a half that fell on Dec. 2 and Dec. 3 was wet to begin with, Allegretto said, and it melted when the sun came up on a 40-degree day.

“It didn’t really do us any favors, because then high pressure set in and trapped the moisture close to the valley floor and never let it go,” she said. “That’s what continued to build up day after day. The high pressure compresses the air and pushes it down. It kept the stratus trapped with nowhere to go.”

It’s a pattern that the Flathead Valley, lake country, sees in December but it’s abnormal in Missoula this early in the winter.

This week’s low sky, combined with hoarfrost clinging to trees and ice clogged on the rivers, hinted of a white Christmas with no snow.

But better days are coming, Allegretto said, and probably in time for Christmas.

It could have negative effects on highway travel, but it’s good news for ski hills, airlines, and school kids on Christmas break, among others.

“I think we’re finally rounding the corner and coming to the December we all know and love,” said Allegretto.

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Mineral County, Veterans Issues Reporter

Outlying communities, transportation, history and general assignment reporter at the Missoulian