Will You Have a White Christmas This Year? Snow Forecasts Say It’s Unlikely.

If you’re dreaming of a white Christmas this year and live in the United States, your best bet is to head to the mountains.

The National Weather Service officially considers a place to have a white Christmas if there is one inch of snow already on the ground, or if new snowfall of at least one inch falls on Christmas Day.

Unless you’re spending the holiday at higher elevations, your chances look bleak. Only about 2 percent of people in the contiguous United States are likely to see a white Christmas. Let’s see if you’re one of them.

There are a few pockets of snow on the ground, especially in the mountains. A storm system that is expected across the middle of the country could bring snow to the Central Plains on Christmas Eve into Christmas Day, but, for the most part, it is expected to deliver rain.

The snow-cover forecast is created from the Snow Data Assimilation System, or SNODAS, which is a computer model from the National Oceanic and Atmospheric Administration’s National Operational Hydrologic Remote Sensing Center.

As with most weather models, the SNODAS forecast will be more accurate the closer we get to Christmas Day. If your area is on the edge of the developing storm system across the Plains, you could see the predictions vary quite a bit over the next few days, depending on exactly where the storm forms.

The areas likely to get snow this year historically have had the highest probability of an inch of snow on Christmas.

Two years ago, NOAA updated the average probabilities of a white Christmas across the United States. Though the report cautioned against comparing the new estimates with those created a decade before, it said that “more areas experienced decreases in their chances of a white Christmas than experienced increases.”

Classic Christmas movies like “Miracle on 34th Street” depict snow falling during the Christmas season in New York City, but Central Park hasn’t seen an inch of snow on Christmas in more than a decade (not to mention the 677 days in a row without an inch or more).

It’s not the first time the city has gone this long without an inch of snow on Christmas Day. The song “White Christmas” was written during one of those long, snowless Christmas spells.

Irving Berlin appears to have begun writing the song in 1938, according to James Kaplan, the author of “Irving Berlin: New York Genius.” This was “when he was spending a lot of time in Hollywood,” Mr. Kaplan said in an interview before Christmas last year.

Mr. Berlin was not particularly happy about being on the West Coast, Mr. Kaplan said, and it’s possible that he felt some nostalgia about the old days on the Lower East Side, where he grew up.

White Christmases were common in New York City at the turn of the 19th century, according to data from the National Weather Service. But by the time Mr. Berlin wrote the song at the end of the 1930s, New York City had not seen a white Christmas since 1930.

Initially, Mr. Kaplan said, Mr. Berlin had written an additional verse for the beginning of the song.

It went something like this: “The sun is shining, the grass is green, the orange and palm trees sway. There’s never been such a day in Beverly Hills, L.A., but it’s December the 24th, and I am longing to be up north.”

But that’s not how the tune was sung by Bing Crosby, who cut that first verse and began with the familiar chorus: “I’m dreaming of a white Christmas, just like the ones I used to know.”Since then, others have uncovered the missing verse and added it to their own versions of the song.

Mr. Kaplan said that Mr. Crosby’s recording of the song, as well as the beginning of World War II, was a “huge accelerator” for its fame and profitability. “Because Bing Crosby’s recording of the song was heard by soldiers and sailors overseas at the beginning of the war,” he said.

The United States entered the war after the attack on Pearl Harbor in December 1941. Mr. Crosby’s recording was released the next year.

According to weather service data for Central Park, in the years after Mr. Berlin wrote the song, there wasn’t snow on Christmas in New York until 1945, a few months after the end of the war.

This year, New Yorkers are once more in a white Christmas drought, with no snow forecast to be on the ground on Sunday or Monday. The last time New York City measured a snow depth or new snowfall of at least one inch on Christmas Day was in 2009.

Historically, New York City has had a white Christmas just 25 of the last 153 years, or about once every six years, according to the National Weather Service.

This year, most of the United States also looks likely to miss out on a classic holiday wonderland.