Much of the northern half of the U.S. could see a milder winter in coming months thanks to a combination of the latest El Niño and ongoing patterns of above-average heat owed to human-made climate change.
That’s especially true of forecasts for Maine and parts of Washington and Oregon.
The recurring weather phenomenon known as El Niño could mean greater rain amounts in Florida’s typical wet season, and still doesn’t preclude a freeze that could put citrus crops at risk. The western Carolinas, too, could see greater-than-usual snow.
The latest predictions from the National Oceanic and Atmospheric Administration could mean short-term relief for Americans who struggled through summer’s heat extremes, but also pose a downside for retailers banking on a flurry of winter-clothing and supplies purchases. The added precipitation, however, points to plenty of snowpack for skiing and snowboarding at popular sites.
According to NOAA’s models, there is a 95% chance El Niño continues through the winter. Generally, whenever there is an El Niño pattern in place, the Northern U.S. has warmer winters, NOAA said.
Meanwhile, across the South and for much of the Atlantic coast into southern New England, the forecast calls for greater chances of a wetter-than-normal winter, said NOAA’s Climate Prediction Center.
Parts of the Northwest, Mountain West and Great Lakes could see greater chances of below-normal precipitation and while a less-snowy winter can mean safer travel, it can hurt the precipitation build relied upon for a healthy crop-growing season later in 2024.
What’s an El Niño and what does it mean for climate change?
Because an El Niño, packing the opposite effect of a cooling La Niña, happens every few years, people often wonder what the relationship is between these weather events and long-running atmospheric warming known as climate change.
“Climate change will likely strengthen any ‘normal’ El Niño effects,” Dr. Stefan Schnitzer, professor of biological sciences Marquette University, told MarketWatch. “The increased global temperatures will add to the El Niño event, especially where rainfall increases.”
Human-made climate change — caused by the greenhouse gas emissions put off by burning coal, oil
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and gas and blamed for accelerating historical climates shifts — has been warming the Earth’s temperature.
An El Niño is the somewhat regular pattern in the tropical Pacific that brings warmer-than-average sea-surface temperatures and influences weather. It emerged earlier-than-expected in 2023.
NOAA in earlier reporting said that the continental U.S. had its ninth-warmest August on record. It also was the 15th-warmest summer on record for the continental U.S. alone. Globally, August 2023 was the hottest on record. Through August, 2023 has been the second-warmest year on record across the world, NOAA said.
Don’t miss: It’s official: This summer was the hottest on record
“Not only was last month the warmest August on record by quite a lot, it was also the globe’s 45th-consecutive August and the 534th-consecutive month with temperatures above the 20th-century average,” said Dr. Sarah Kapnick, NOAA’s chief scientist.
“Global marine heat waves and a growing El Niño are driving additional warming this year, but as long as emissions continue driving a steady march of background warming, we expect further records to be broken in the years to come,” she said.
Read: Already roasting in extreme heat? 2024 could be even hotter, NASA scientists warn.
What about El Niño and winter weather in the U.S. South and Midwest?
El Niño tends to bring wetter conditions to the Southeast. Florida, in particular, experiences higher-than-average rainfall during El Niño winters. This can lead to localized flooding, especially in low-lying areas and regions prone to heavy downpours.
According to the National Weather Service in Tallahassee, Central Florida averages between 8 to 10 inches of rainfall during a typical winter. But during El Niño winters, that rainfall total rises to between 10 and 13 inches.
As for other parts of the South, El Niño typically means more precipitation, which in mountain areas, can mean snow.
Because the jet stream is displaced farther south, El Niño brings frequent storms across these areas, leading to above-average precipitation and below-average temperatures. This combination typically means more snow in Western North Carolina. In fact, some of the biggest seasonal snow totals have come during El Niño winters. Most notably, in the winter of 1968-69, more than 48 inches of snow fell in Asheville, N.C. And more recently, the winter of 2009-10 was unusually snowy with a whopping 39 inches accumulating.
In the Midwest, El Niño normally results in warmer and drier winters, meaning less snow.
“During an El Niño winter, the polar jet stream shifts northward, reducing the extremely low temperatures that normally swing down into the Midwest, including Wisconsin, Illinois, Michigan, and so on,” said Marquette’s Schnitzer.
Schnitzer reminds that weather variability is always unpredictable. Forecasts use models and historical patterns to try to offer an educated guess about the coming months.
“Occasionally we can get very cold temperatures and snow during an El Niño. It depends on what other weather systems blow through the area,” he said.
What is El Niño’s impact on skiing and snowboarding?
Of course the amount of precipitation can impact how much snowfall is expected at higher elevations and what kind of season major skiing and snowboarding destinations can expect.
During the early parts of the winter season, through the rest of 2023, data suggests a normal- to drier-than-normal period for most of the western U.S. As for the eastern U.S., predictions look wetter than normal, says meteorologist Chris Tomer, in an outlook for the On the Snow website, with a prediction closely aligning with other experts looking at NOAA’s data.
By January, says Tomer, the bulk of the El Niño-driven snowfall typically occurs across parts of the West with a strong subtropical jet.
“The pattern suggests a higher likelihood of atmospheric river (AR) events. In the Northeast, normal- to above-normal snowfall appears possible. Be warned, though. “The pattern suggests that NorEaster storm systems are more likely,” Tomer said.
To him, that means New England ski areas could see a particularly advantageous snowy winter, which would be a welcome snapback from last season’s winter on the East Coast.
Many Colorado ski areas, including Summit County resorts, Loveland, Telluride and Arapahoe Basin, also stand to be among the biggest snow “winners,” says Tomer. He’s also upbeat for accumulation for New Mexico ski areas and California ski areas in the Sierras.
“El Niño historically doesn’t favor any particular outcome for Wasatch, Aspen Snowmass and Vail [in Colorado],” he added. “However, if the Modoki contribution [when the warming is generated in a different part of the Pacific Ocean] to this El Niño increases, then all of these resorts could tilt a little higher to 105% to 110% of normal winter snowfall.”
