If you live in Marquette, Mich., Presque Isle, Maine, or Lake City, Colo., your chances of having a white Christmas are, as usual, pretty high. And thanks to a massive blizzard lumbering through the West, the Texas Panhandle, big swaths of New Mexico, and the Kansas prairies are also looking at up to a foot of the white stuff just in time for Christmas morn.
Most of the rest of the country? Let's put it this way: Santa might have to change his sled runners out for tires.
After two straight years of "Snowpocalypse" storms and 50-percent-plus overall snow cover across the US by Christmas, frozen precipitation is considerably down this year, with only about 20.9 percent of the country currently with at least an inch on the ground – the National Weather Service's requirement for a "White Christmas" designation. Overall US snowfall for the month of December is down by 73 percent from last year, or 55 percent below average. The overall snow cover is the lowest since 2003, when the country had 21.2 percent snow coverage by Dec. 19.
And while a dangerous blizzard began on Monday to snarl traffic along I-40 in the West, the system isn't expected to bring much snow eastward.
The culprit: The North Atlantic Oscillation (NAO), a permanent atmospheric feature that jogs and spins over Greenland. The last two years – which brought snow and frost even to Florida – the NAO helped push large troughs of frigid Canadian air across the East and deep into the South, resulting in a cavalcade of record-breaking snows that blanketed major cities like Washington, D.C., and New York City and turned Atlanta into a block of ice.
In contrast, average temperatures this year are up across the East, with many areas recording five-year temperature highs. Meanwhile, desert border towns like Deming, N.M., have already seen impressive snow events.
"If you look at the large-scale weather pattern, the cold weather that we had the last two years was the result of a trough camping out over the eastern US, and the difference this year is that the intermountain West has been the place where the trough has been living," says Doug Miller, an atmospheric science professor at the University of North Carolina-Asheville. "So while they're having pretty amazing amounts of snow as well as cold temperatures, [the East] has been socked in with high pressure, which generally means fair weather."
Dr. Miller and his grad students study winter storm dynamics by sending up weather balloons into every blizzard that batters the southern Appalachians. Last year, the team had launched three balloons by Christmas compared to one so far this year.
The pattern isn't likely to change soon, meaning a brown Christmas is likely for at least 70 percent of the US this coming weekend.
Until this year, "a lot of the country has been pretty spoiled" when it comes to getting a white Christmas, says Carrie Olheiser, the operations manager at the National Operational Hydraulic Remote Sensing Center in Chanhassen, Minn. "This is the brownest we've seen it in quite a while."
Don't count Old Man Winter out just yet, though. Accuweather.com has predicted a "brutal" winter for part of the Midwest and the Great Lakes Region, a prognosis driven by a Pacific weather system – La Niña – which, historically, produces colder winter temps at least in the northern half of the country. But even that prediction says snow accumulation is likely to be far less than the kind of records set last year in places like Kent, Ohio, which recorded 116 inches of snow.
The shift has been a winter enthusiastst's bane, and has ski lift operators across the East concerned. Thanks to the shifting trough, Little Rock, Ark., has seen more snow than Syracuse, N.Y., this December.
While the dynamics of La Niña and the NAO are still not fully understood by meteorologists, it's unlikely that the snow cover shifts are related to broader climate change theories, says Miller. "And I'd caution people, we're not even officially into winter yet, and where we might get complacent and think it's not going to be a bad winter, January and February could still be much colder than normal," he says. "It doesn't take much for it to snow, even in Atlanta."