A rare disruption of the polar vortex high above the Arctic is underway, and it could affect winter weather across the Great Lakes region in the weeks ahead.

Winds circling the North Pole at about 100,000 feet dropped sharply in late October, falling from 22.13 meters per second on Oct. 25 to 5.44 meters per second by Nov. 2, according to The Watchers. That Nov. 2 reading was well below the long-term average and below any previously recorded value for that date, the outlet reported, citing NASA data going back to the late 1970s.

The disruption could qualify as a sudden stratospheric warming (SSW) event. An SSW occurs when the air high above the Arctic heats up rapidly and the winds that keep cold air bottled over the pole weaken or reverse direction. These events typically happen in the middle of winter, not early November, NBC Chicago reported.

If the wind reversal meets the formal threshold, it would be the earliest major SSW in records going back to the late 1950s, according to NBC Chicago. The earliest previously recognized major event occurred around Nov. 28, 1968.

What it means for the Kenosha area

A polar vortex disruption does not automatically send Arctic air into the Midwest. It can take weeks for changes roughly 20 miles above the ground to reach the surface, NBC Chicago reported. Where that cold air spills is also uncertain.

For the Great Lakes, the greatest influence would likely arrive from late November into December, according to Fox 2 Now. The result could be alternating warm and cold periods rather than a sustained stretch of winter weather.

Judah Cohen, an atmospheric scientist at MIT, told FOX Weather the disruption is likely "the largest, earliest disruption of the polar vortex on record," as Futura-Sciences reported. Cohen said the timing, strength and impacts remain highly uncertain.

AccuWeather long-range meteorologist Alex DaSilva told Newsweek that because the event is happening so early, there is less cold air available than during midwinter. "I don't think the cold outburst is going to be that significant compared to if this happened during the heart of winter," DaSilva said.

El Niño complicates the picture

A very strong El Niño is the other major factor shaping this winter. The Climate Prediction Center (CPC) called El Niño the "dominant" large-scale climate influence in its November outlook, issued Oct. 31. El Niño winters historically favor warmer-than-average conditions around the Great Lakes, NBC Chicago reported.

The CPC said the possible SSW and a forecast negative Arctic Oscillation could compete with El Niño's circulation patterns, particularly over the eastern United States. That tug-of-war adds uncertainty to the forecast for the region.

NOAA's seasonal outlook still favors above-average temperatures across the Great Lakes for December through February, even while acknowledging the polar vortex disruption, according to NBC Chicago. DaSilva told Newsweek that El Niño "will still be the primary driver behind this winter because it's so strong."

Near-term forecast

The National Weather Service office in Milwaukee issued an area forecast discussion Nov. 5 showing no winter weather watches or warnings for Wisconsin. The short-term outlook called for cooler conditions Friday and Saturday, with lows dropping into the mid-to-upper 20s inland of Lake Michigan by Friday night. A warming trend was expected through the weekend, with highs returning to the 60s early the following week.

Late November into December remains the period to watch for any cold-air intrusions linked to the polar vortex disruption.