This was the last nationwide White Thanksgiving. How Super El Niño and the polar vortex could shape 2026

THE TAKEAWAY

How will an expected Super El Niño interact with the polar vortex this winter, and what is the likelihood of a nationwide white Thanksgiving this year?

2019 was the last Thanksgiving when more than 20 states had significant snow coverage, when several winter storms combined to bury much of the country west of the Mississippi River in snow.

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A major snowstorm ripped across the Rockies two days before Thanksgiving, dropping over 30 inches of snow across the Front Range, including between 12 and 15 inches across the Denver metro area, snarling holiday travel.

Travel worsened Wednesday as widespread snow moved across the Plains and Upper Midwest, burying the regions under 8 to 12 inches of snow.

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Parts of northern New England also saw heavy snow on Thanksgiving Day itself, particularly across the interior of Maine.

Looking ahead to this year's Turkey Day, widespread snow is contingent on how far south arctic air is able to push into the Lower 48 and whether storm systems are able to overlap and interact with that cold air.

"El Niño is generally not conducive to White Thanksgivings across the Northern Tier and Midwest due to a warm ridge of high pressure that sets up," the FOX Forecast Center said.

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The El Niño climate pattern is rapidly strengthening, with NOAA expecting Super El Niño conditions to take hold later this year.

El Niño is one of three phases of a climate cycle called the El Niño-Southern Oscillation (ENSO). It describes natural temperature changes in the central Pacific Ocean that alter atmospheric circulation and can greatly influence global weather.

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El Niño describes warmer than average water across the equatorial Pacific, while La Niña describes colder than average water conditions, and ENSO neutral refers to a state where temperatures are close to average.

Water temperatures in the central equatorial Pacific averaged more than 2 degrees Celsius above normal in September, which is considered Super El Niño territory.

Temperatures have to remain 2 degrees above average for three months to officially be considered a Super El Niño event.

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El Niño does generally bring a stormy winter pattern to California and the Southern Tier of the country by nudging the Pacific jet stream southward. The jet stream acts as an atmospheric conveyor belt for storms.

This pattern has already begun to emerge, as evidenced by storms that caused deadly flooding across the Southwest last week, with another powerful system targeting the region this weekend.

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With regard to the second ingredient for snow — cold air — El Niño's warm Pacific air generally limits the amount of arctic air that's able to drop south from Canada.

The polar vortex is a wall of wind that encircles the North Pole and acts as the gatekeeper for the coldest air on the planet.

When the polar vortex weakens, it allows that cold air to drop to the surface and spread into the Lower 48.

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"It is true that El Niño can increase the odds of a weakened polar vortex," the FOX Forecast Center said.

"But, this usually occurs late in the winter, not during Thanksgiving. Even when it does break down, it usually influences the wintertime climate across Asia, Europe and Greenland, and is more subtle for North America."

However, most long-range forecast models show a major disruption of the polar vortex beginning in the second week of November, which would be the earliest on record.

That could set up a tug of war between cold Arctic air spilling south from Canada and milder Pacific air associated with El Niño.

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Whichever wins out could determine whether the country will see its first widespread White Thanksgiving in seven years.

"Trends in the computer modeling will need to be watched closely as they sort out this potentially unprecedented pattern," the FOX Forecast Center said.