Daytime highs across Wyoming were in the high 50s to low 60s on Monday. Meanwhile, freezing temperatures were reported along the Gulf Coast.
What the heck is going on with Wyoming's weather?
While the Eastern U.S. and half of Montana were smothered by snow and subzero temperatures, Wyoming has remained abnormally warm and dry. It's a persistent pattern that's keeping Cowboy State Daily meteorologist Don Day up at night.
"When you have extremes like this right next to each other, if one thing changes, your extreme can flip," he said. "We're in a log jam right now, and what happens when a log jam breaks? It's going to break, but I'm not sure about the timing."
The "log jam" Day referenced is a stubborn ridge of high pressure over the Bering Strait off the coast of Alaska. Couple that with Wyoming's position, straddling the Continental Divide, and the winter weather many Wyomingites have been waiting for is being funneled elsewhere.
Will there be a reversal? Eventually, but it could be another week or two before winter weather reaches Wyoming, but there will likely be other extreme weather in the meantime.
"As persistent as this pattern has been, it's going to take something to bust it," Day said. "These blocking patterns can go on for weeks. We can have a 180 eventually, and I think that's going to happen, but this blocking pattern is really holding things up."
Log Jam In The Jet Stream
While Wyoming experienced a warm, sunny weekend, the eastern U.S. got lots of snow and subzero temperatures, courtesy of an influx of cold air from the Arctic. It was in the 60s on Friday while Billings, Montana, got several inches of snow.
Some of that snow dipped into northern Wyoming, so the Cowboy State hasn't been entirely devoid of snow. Still, the lack of snow across most of the state has been unsettling.
"Anybody who was watching football this weekend saw how cold and snowy it was from Boston to Cleveland, while the Rockies were unseasonably warm," Day said.
According to Day, two factors are making it hard for winter to penetrate into Wyoming. The first is the high-pressure ridge that's sticking to the all-important jet stream.
"There is a big jet stream blocking pattern that's been in place for the last couple of weeks up in the Bering Strait," he said. "What it's doing is causing the weather to repeat. Pacific Air is coming into the Rockies and the western high plains, while Arctic air is sliding out of Northwest Canada into the north plains and the Great Lakes."
That blocking ridge has blocked cold temperatures and precipitation from reaching into the western U.S. In a sense, Wyoming's winter weather is being funneled eastward because it can't get here.
Then there's the Continental Divide. The dividing line of mountain ranges that splits Wyoming into two distinct halves is creating a "forecasting paradox" that was evident over the weekend.
"You can have one part of the state experiencing extreme weather that's completely different from the other extreme from the other side of the Divide," Day said. "It is a bit anomalous to have these extremes right next to each other, but these will happen during the course of the winter."
Day said the two factors combined have created a meteorological "log jam" that isn't showing any signs of letting up. That's why the eastern half of Montana, the Dakotas, and sections of northeast Wyoming got winter weather while the majority of Wyoming didn't see a single snowflake.
"There was record cold in the Yukon last week," he said. "You would think Wyoming would get some winter weather. Montana did, but for Wyoming, that Arctic outbreak was a swing and a miss."
You'll Be Blown Away
Day isn't sure when the log jam preventing Wyoming's winter will break, but he's anticipating some intense weather in the meantime. Anyone who doesn't like hurricane-force winds might want to avoid driving on the highway later this week.
"We're not going to have crystal clear blue skies, calm winds, and 60-degree temperatures while we wait for snow," he said. "We are probably going to have another major wind event sometime in the middle of this week because of this extreme contrast in air masses."
Last week's windstorms were caused by the vacancy over Wyoming when cold Arctic air moved on and was replaced by warm Pacific air. The gap between the two air masses led to strong winds that blew over at least 28 semi-trucks in a single day.
Day isn't sure whether this week's wind event will be as intense as last week's, but he's confident the winds will be "screaming" across Wyoming.
"It's hard to repeat what happened last week, and I don't know how intense this week's wind will be, but we're going to have some definite challenges on the interstates with really strong wind gusts," he said.
Meanwhile, whatever snow Wyoming gets will overwhelmingly favor the mountains. Those are the only spots where it's cold enough for snow to stick, and December's weather tends to favor snow in the high elevations while the rest of Wyoming goes without.
"What's really good for the mountains is not good for the plains," Day said. "There is going to be several rounds of high-elevation snow, starting Tuesday and continuing through next week, while there may be some smatterings of snow on the plains."
Even if there are "smatterings of snow," it's more likely to be blown up and over the highways than settle onto the landscape. That'll make travel more hazardous.
Weather Challenges
Day admitted that the current prevailing weather patterns are making his job more difficult. The blocking pattern in the jet stream could break tomorrow or persist into January.
"I'm having a very difficult time handling these extremes with computer modelling and trying to understand what is going to happen next," he said. "The severe winter cold, which we certainly have potential for this winter, is going to stay away until this pattern breaks."
Given how this pattern is holding up, Day said most of Wyoming may remain warmer than average for the next two weeks. That'll mean no White Christmas this year.
"The question going forward is, will the current pattern that has saved us from the Arctic cold so far continue into January and February?" Day said. "These blocking patterns don't go on for months, but they can go on for weeks."
The consolation prize will be more dry days with hurricane-force winds. There will be much rejoicing on Wyoming's highways.
Day isn't ruling out a heavy winter, with plenty of snow and subzero temperatures, as he predicted for the 2025-2026 season. However, while the log jam created by the jet stream in the Bering Strait and the omnipresent Continental Divide persists, an influx of winter weather "isn't on the table" yet.
"The trajectory of the weather is stuck for the next week or so," he said. "I've seen warm, dry spells in December and many a Christmas where there's no snow on the ground. We certainly have the potential for a severely cold, snowy winter, but I'm reluctant to say that we're going to get direct hits from the Arctic air until this pattern breaks."
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
