The Arctic polar vortex is about to go "haywire," and meteorologists are trying to figure out what an extraordinarily early disruption of the frigid air mass high above the North Pole will mean for Northern Virginia's winter weather.
"Everybody's hair is on fire in the meteorologist community," Judah Cohen, a research scientist at the Massachusetts Institute of Technology and director of seasonal forecasting at Atmospheric and Environmental Research, told Scientific American.
The uncertainty is especially significant this year because El Niño, which typically brings milder winters to much of the northern United States, is another wild card. An unusually early disruption of the polar vortex could complicate that outlook, but experts don't yet know whether it will send bitterly cold Arctic air plunging into Virginia or somewhere else entirely.
For now, meteorologists with the private weather company AccuWeather say the shifting polar vortex isn't expected to unleash a bitterly cold blast across the United States. Northern Canada isn't particularly cold to begin with, and the coldest available air is expected to flow toward Siberia instead.
Parts of the United States will turn cooler and wetter during the first half of November, with more significant cold outbreaks possible later in the month and into December as atmospheric patterns change, AccuWeather said.
Northern Virginia had a slightly warmer-than-average October, according to AccuWeather. In the first half of November, as the jet stream flows right over top of the Washington Metro Area, the sunny stretch will give way to rain and unseasonably wet conditions. Get ready for slippery leaves and temperatures more in line with seasonal norms.
Rain has arrived already in some areas. Later this week, thunderstorms could come with it, and toward the latter part of the month, chilly temperatures could finally settle in.
The last time the polar vortex experienced a disruption this early in the season was on Nov. 28, 1968, according to Cohen. Scientific American said in a report Wednesday that the vortex is "about to go haywire."
Normally, the Arctic polar vortex spins like a top high above the North Pole, with strong winds circling a pool of bitterly cold air and keeping it largely confined to the Arctic. But like a spinning top knocked off balance, the vortex can wobble, stretch or even split apart when large atmospheric waves rising from lower altitudes disrupt its circulation.
When that happens, bitterly cold Arctic air can spill southward into the United States, sending temperatures plunging well below normal and sometimes locking large parts of the country into a deep freeze for days or even weeks. Such outbreaks are more common during the heart of winter, when Arctic air is at its coldest.
AccuWeather expects the polar vortex to weaken and shift out of its usual position in November, while the jet stream develops large bends that ordinarily allow frigid Arctic air to plunge southward.
Complicating the outlook is El Niño, characterized by unusually warm waters in the tropical Pacific. It generally favors milder winters across much of the northern United States, but the disruption of the polar vortex introduces another variable that could alter the usual weather patterns.
Cohen cautioned in a separate interview with USA Today that the last El Niño winter, in 2023-24, featured two sudden stratospheric warming events but was exceptionally mild in the eastern United States.
"In short lots of uncertainty!" he said.
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