Dreaming of a White Wyoming Christmas? Keep dreaming.
After a concerning month of above-average temperatures, below-average precipitation and multiple intense windstorms, the same weather patterns that dominated December are looking to continue into the Christmas holiday.
Wyoming doesn't have a great track record for snow on Christmas. Historically, it's more likely to have a White Halloween than a White Christmas.
This year, the decks are especially stacked against the Cowboy State. It's a forecast that's frustrating meteorologists like Don Day.
"In the last three weeks, we've had 6 feet of snow in the Snowy Range followed by two weeks of no snow, Arctic outbreaks in the east, and multiple high wind events," he said. "This winter season is off to a nightmare start, and we're still trying to get a handle on it."
The definitions of a "White Christmas" are different. If everything lines up, some parts of the state could see snow before the holiday's over, but most will go without.
"I'm pretty confident most of Wyoming will be warm and dry on Christmas Day," Day said.
Stubborn Stream
For most of December, Wyoming's weather has been dictated by a persistently stubborn jet stream over the Bering Strait. Day described it as a "logjam" that's blocking and redirecting the winter weather that would ordinarily reach into the Rocky Mountain region.
"It's like a high-pressure ridge on steroids," Day said. "The long-range seasonal modeling showed high pressure in the North Pacific in a location that does favor cold weather coming into the western United States. But it has become so intense that it's ended up realigned where the cold outbreaks are going."
Wyoming's winter hasn't failed to manifest. It just missed the mark by over 700 miles.
"Right now, we're locked behind a door that's blocking an Arctic outbreak," Day said. "It's definitely been cold and wintry to our north and east, but that's where the shift of the weather has gone. The blocking pattern is directing everything away from us."
Historical precedent shows that stubborn jet streams can last for several weeks. Based on the long-range models and short-term forecasts, Day doesn't think this stream will break before Christmas.
What won't help Wyoming's winter is a second jet stream logjam. Day said another seasonal logjam, similar to the one over the Bering Strait, typically forms north of Greenland around this time.
"We could actually see that developing next week," he said. "If we get two logjams, that really complicates things as it'll impact the behavior of the jet stream across the Northern Hemisphere."
Day acknowledged that these persistent patterns are "concerning," and will be increasingly concerning if they persist into January and February. Unfortunately, there was no way to anticipate this sequence of events.
"We did not foresee a block of this intensity," he said. "That was a bust in our long-range forecasts, and it's definitely a concern everywhere in North America. I don't know anyone who's enjoying this. It's gross."
Where There's White, There's Hope
December hasn't been a complete bust for winter weather. The unambiguous winners are the western mountain ranges, which have been slowly but steadily building their snowpacks.
"You don't want to go through all of December without getting some moisture, and the mountains of Western Wyoming, Montana, Idaho, and the Pacific Northwest haven't been completely blocked from getting some snow," Day said.
The problem is that those Arctic outbreaks haven't been able to penetrate further south into southern Wyoming, Colorado and Utah. That'll remain an ongoing concern as the winter season progresses.
If anyone wants to experience a White Wyoming Christmas this year, their best bet is the mountains of western Wyoming. They've already gotten some snow, and there's a good chance they'll get some more in the days leading up to and including Christmas.
Winter weather that's good for Wyoming's mountains tends to be less favorable for the plains, as cold air warms and loses moisture as it descends from the high elevations. However, Day said there's "a chance" that some snow could descend from the mountains on Christmas Day.
"I'm pretty confident that the eastern side of the state is going to be warm and dry, but the western counties and maybe even the south-central parts of the state may actually see something in the form of some snow on Christmas Day," he said.
If your definition of a White Christmas is a snow-covered landscape, it's too late for that. If your definition is snow falling on Christmas, some parts of Wyoming might be indulged.
"Maybe," Day said. "It's at least a week away, and something could change between now and Christmas."
Andrew Rossi can be reached at arossi@cowboystatedaily.com.
