Stratospheric warming developing over the Arctic forecast to weaken the polar vortex and influence February weather
Meteorological forecasts show a major sudden stratospheric warming event forming over the Arctic, expected to cause significant weakening of the polar vortex in early February 2026. The resulting atmospheric disruption may alter jet-stream dynamics and increase the risk of Arctic air intrusions into North America and northern Europe during the second half of February.
Frozen structures in Odesa Ukraine on January 19, 2025. Credit: Anton Gerashchenko
Meteorological observations and high-resolution model data indicate a rapid temperature rise in the Arctic stratosphere during late January, characteristic of a major sudden stratospheric warming (SSW) event.
These events occur when upward-propagating planetary waves disrupt the polar night jet, causing the stratosphere, between roughly 10 and 50 km (6 and 31 miles) in altitude, to warm rapidly by tens of degrees within days.
Forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Global Forecast System (GFS) indicate that stratospheric temperatures at 10 hPa will rise by more than 40°C (104°F) in parts of the polar regions.
Zonal wind speeds are expected to weaken markedly, signaling a strong disturbance of the polar vortex, though a complete wind reversal, the main indicator of full vortex collapse, is yet to be confirmed.
The ongoing deformation of the vortex is likely to result in a split, with one core going toward North America and another toward Eurasia. This configuration promotes meridional air flow, allowing Arctic air to move southward and enhancing the potential for high-latitude blocking over the Arctic.
Surface effects from such stratospheric disturbances generally appear one to three weeks after the initial warming, as downward-propagating anomalies influence the troposphere.
Forecast models suggest the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) could enter negative phases in February, conditions typically associated with colder air over continental regions of the Northern Hemisphere.
This pattern would favor the year’s second phase of repeated cold-air intrusions into central and eastern Canada and the United States. Meanwhile in Europe, colder-than-average conditions are forecast for northern and northwestern regions, while southern Europe may remain near or slightly above average.
The magnitude of surface cooling remains uncertain and depends on the persistence of stratospheric-tropospheric coupling and the precise evolution of the jet stream.
Current forecasts show a moderate-to-strong coupling signal developing through early February, consistent with a downward transfer of stratospheric anomalies to the lower atmosphere.
This event develops under the background conditions of a weakening La Niña in the equatorial Pacific. While La Niña can modulate jet-stream behavior and occasionally enhance the atmospheric response to stratospheric disturbances, the influence is indirect and probabilistic. Current seasonal outlooks show mixed surface temperature anomalies for February 2026, with cold risks mainly confined to higher latitudes.
If the downward coupling strengthens as expected, the Northern Hemisphere could experience a period of amplified temperature contrasts, increased storm activity, and regionally enhanced snowfall through mid- and late February 2026. As the stratospheric system transitions toward its seasonal weakening in early spring, further warming episodes may finalize the breakdown of the winter polar vortex.
References:
1 Stratospheric Warming Alert: A Massive Shift in the Polar Vortex is Forecast for early February – SWE – January 23, 2026
2 Major polar vortex disruption brings Arctic surges across North America and Europe through January and early February 2026 – The Watchers – January 17, 2026
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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