Polar Vortex disrupted at the earliest point in a calendar year on record — what happens next?
The Polar Vortex has been disrupted at the earliest point in a calendar year on record, according to analysis from the FOX Forecast Center. What exactly does that mean?
THE TAKEAWAY
The Polar Vortex has been disrupted at the earliest point in a calendar year on record, according to analysis from the FOX Forecast Center.
Don't run for the hills or dust off the snowplow just yet – this doesn't exactly mean temperatures will drop overnight, or at all.
The polar vortex is a band of strong winds that circles the North Pole from roughly 55 degrees north latitude — approximately the latitude of Ketchikan, Alaska — about 10 to 30 miles above the Earth.
Seasonal weather patterns in the lower atmosphere can send powerful atmospheric waves into the stratosphere. If those waves are strong enough, they can disrupt the polar vortex by weakening, displacing or splitting the circulation — and, in some cases, reversing its normally strong westerly winds.
HOW DOES THE POLAR VORTEX INFLUENCE WEATHER?
The disruption can alter the circulation of the atmosphere and increase the chances of Arctic air spilling southward.
In a season of weather extremes dominated by a Super El Niño, this polar vortex disruption could also be one for the books, as it could become the earliest major disruption on record, with potential implications for weather patterns through the rest of fall and eventually into winter.
So, will this earliest disruption on record bring loads of snow and train a polar express surge of cold into your town? Not exactly.
While a polar vortex disruption can lead to colder weather across North America, that does not appear to be the immediate outcome in this case.
COULD SUPER EL NIÑO PUT A DAMPER ON LAKE-EFFECT SNOW THIS WINTER?
"So far, models continue to show no major cold air outbreaks in the future," the FOX Forecast Center said.
Changes in the stratosphere don't translate into colder weather at the surface overnight. It can take several weeks for those changes to work their way downward and influence the jet stream and larger weather patterns.
HOW THE BREWING SUPER EL NIÑO WILL BENEFIT VARIOUS REGIONS ACROSS THE COUNTRY
Even if this becomes the earliest major breakdown on record, that does not necessarily mean colder air will arrive earlier.
Any potential impacts across North America would be more likely toward late November or December.
For now, forecast models continue to show the coldest air pooling across Eastern Europe and Siberia. Meanwhile, North America remains much warmer than average, limiting the chances for a prolonged stretch of Arctic air across the U.S.
The rapidly strengthening El Niño climate pattern is also expected to play a major role in North American weather through November and into December, with a Super El Niño expected tp be declared later this year.
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El Niño has already begun to strengthen the Pacific jet stream, which is carrying mild air from the Pacific, as well as more storms across the country.
That pattern will support above-average temperatures and make it more difficult for colder air to settle in for an extended period.
The Climate Prediction Center’s long-range forecasts continue to reflect this pattern, favoring above-average temperatures across much of the northern United States — including the Pacific Northwest, Northern Plains, Upper Midwest, Great Lakes and Northeast — through December.
Brief cool spells remain possible, but the overall pattern currently favors a milder-than-average November and early winter.
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