Major sudden stratospheric warming forecast, final polar vortex collapse of the season signals mid-March freeze

An analysis by Andrej Flis of Severe Weather Europe (SWE) indicates that the second polar vortex collapse of 2025 is expected to occur in mid-March. This follows the previous collapse in mid-February, which brought record-breaking cold temperatures across the United States.

This event is expected to be much stronger than the previous one and will mark the final collapse of the season. The next polar vortex in the stratosphere will not form until the 2025-26 winter season.

The wind forecast indicates a reversal from the usual westerly to easterly flow, signaling a major sudden stratospheric warming (SSW) event. SSW leads to a temperature increase in the stratosphere, disrupting circulation patterns.

SSW events are notorious for destabilizing the jet stream, the high-altitude wind band that steers weather systems. A weakened or meandering jet stream often opens the door for frigid Arctic air to plunge into mid-latitudes, while shoving milder air eastward.

Current models suggest cold air is pooling over western Canada and the western United States, potentially priming the region for biting freezes, heavy snow, or even ice storms, depending on local conditions. Meanwhile, a warm air mass is retreating from the eastern U.S., suggesting stark temperature divide that could fuel extreme weather contrasts—think blizzards in the Rockies while the Southeast basks in unseasonable warmth.

The placement of low-pressure systems will be critical. If they anchor over the central U.S. or Great Lakes, they could drag cold air southward, threatening crops in the Plains, straining energy grids with surging heating demands, and snarling travel with late-season snowfalls.

Past SSW events, such as the March 2018 “Beast from the East” in Europe, brought heavy snowfall and paralyzed transportation, and North America could face a similar scenario. If these systems shift northward, the U.S. heartland may be spared, with cold instead directed into Canada’s Prairie provinces, where impacts could include livestock losses and iced-over hydroelectric lines.

Current forecasts remain preliminary, as models are only beginning to capture the early stages of the SSW aftermath, with outcomes hinging on how the vortex fragments and where high-pressure anomalies settle.

By mid-March, the weakened vortex—split into fading cores over Eurasia and North America—may leave weather patterns chaotic for weeks, with impacts lingering into April.

References:

¹ A Powerful Full Polar Vortex collapse is now Forecast for mid-March, with an impact on Weather patterns over North America – SWE – February 28, 2025