A historic atmospheric event has turned Canada’s winter forecast upside down as the stratospheric polar vortex ground to a halt and reversed direction around November 10, 2026, marking a rare and unusually early disruption.
Stratospheric Winds Reverse
High above the Arctic, the powerful circulation of winds swirling roughly 30 kilometres up reversed for November. According to The Weather Network, the stratospheric polar vortex slowed dramatically and changed direction instead of strengthening as it normally would at this time of year.
Wind speeds dropped to approximately -0.1 metres per second by November 10. Typical seasonal winds run around 25 metres per second, leaving current speeds at just four per cent of normal values.
Mild Air Dominates
Despite the high-altitude disruption, central Canada continues to experience unusually mild conditions. A powerful El Niño and an energized Pacific jet stream are helping maintain above-seasonal temperatures across the country.
The situation is further complicated by mild weather extending deep into the Canadian Arctic. Much of the coldest air sits on the other side of the pole over Siberia rather than on the North American side.
Pacific Pattern Shifts
Attention now turns to the final ten days of November for clues about changing surface weather. According to the report, European ensemble forecast models suggest the eastern Pacific oscillation may move into negative territory.
This negative pattern can encourage higher pressure near Alaska and the northeastern Pacific. A downstream trough could then develop over North America, creating a pathway for colder Arctic air to move south.
Polar Vortex Recovery
Forecast models suggest stratospheric winds could recover rapidly during the third week of November. Winds are expected to climb back toward and eventually exceed 25 metres per second.
Major stratospheric warming events and polar vortex disturbances can create ripple effects throughout the Northern Hemisphere. These shifts can influence atmospheric circulation for weeks after the initial event.
Winter Forecast Timeline
Meteorologists are watching specific dates as the season gets underway:
* November 10–13: Historic polar vortex disruption and wind reversal.
* November 14–20: The polar vortex begins recovering, with stratospheric winds expected to strengthen.
* November 20–27: Attention turns to the northeastern Pacific and Alaska.
Will atmospheric ridging develop and create a pathway for colder air to move south?
* Early December: Forecasters will monitor whether a lasting blocking configuration emerges and if the broader atmospheric setup transitions into winter conditions.
Questions About the Polar Vortex Reversal and Recovery
What caused the polar vortex to reverse in November?
The study notes that this timing is exceptionally bizarre, given that a robust El Niño generally supports a more vigorous polar vortex. Instead, the atmosphere is doing almost the opposite of what historical patterns would suggest.
When will the polar vortex return to normal?
Computer simulations indicate that winds in the stratosphere may bounce back quickly in the third week of November, rising toward and ultimately passing 25 metres per second.
Is Canada guaranteed to get an instant blast of winter weather?
No, even a severe high-altitude breakdown above the Arctic region fails to guarantee an immediate surge of cold winter weather across Canadian provinces. It can take several weeks for the consequences of a significant polar vortex breakdown to propagate downward through the atmosphere and affect ground-level weather.
When is the next major weather update scheduled?
The Weather Network’s winter forecast is scheduled for release on November 25, 2026.
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