The Northern Hemisphere polar vortex is forming normally over the Arctic and was stronger than average by NASA’s wind diagnostic in mid-September 2026. The developing very strong El Niño could favor atmospheric wave patterns that weaken the vortex later in winter, with seasonal guidance showing a possible weakening during January and February 2027.
A major polar vortex disruption has begun and is forecast to send Arctic air into much of North America and Europe through mid and late January 2026. The event will bring freezing temperatures and winter weather as the vortex weakens following a stratospheric warming episode. A second, stronger outbreak is forecast to occur during the last part of January as the core of the vortex splits into two halves, each driving cold Arctic air into Europe and North America in February.
A stratospheric warming event over the North Pole is expected to weaken the polar vortex and may lead to a core split around January 25, 2026. The disruption could cause another surge of Arctic air, bringing below-average temperatures and snow to large parts of the U.S. and Europe.
A sudden stratospheric warming event has begun, deforming the Polar Vortex and setting the stage for a colder start to winter across the United States, Canada, and Europe.
An early stratospheric warming developing over the Arctic in late November 2025 is raising the likelihood of colder conditions and increased snowfall across parts of the United States, Canada, and possibly Europe in December.
An early-season stratospheric warming event is forecast to weaken the polar vortex in the coming weeks, potentially influencing winter 2025–26 weather across North America and Europe.
Forecast data indicate an early weakening and displacement of the stratospheric polar vortex over the Arctic in October 2025, as a developing high-pressure anomaly over Greenland interacts with the circulation earlier than usual, increasing the chances of colder air movement toward the mid-latitudes of North America and Europe.
A rare stratospheric warming event is disrupting the Antarctic polar vortex in September 2025, with forecasts suggesting wetter southern Australia, drier eastern Australia, and a higher chance of abnormally hot days.
The polar vortex forming over the Northern Hemisphere in 2024 is at its weakest point for early October in the last 40 years, with potential consequences for winter weather patterns across North America and Europe. The vortex’s unusual behavior this season could lead to significant disruptions in cold outbreaks in parts of the eastern United States, Canada, and Europe.
The polar vortex, a large area of low pressure in the upper atmosphere that typically sits over the poles, is set to weaken as a sudden stratospheric warming (SSW) event unfolds in the northern hemisphere. This event has the potential to have a significant impact on winter weather, as it allows cold Arctic air to escape and cause outbreaks in Europe, Asia, Canada, and the United States.
