The latest meteorological models confirm a fundamental event – the final collapse of the polar vortex is coming. This atmospheric phenomenon at the turn of winter and spring will split the high-altitude flow into two separate cores, which will significantly affect the weather throughout the northern hemisphere during March. While North America prepares for the harsh invasions of the arctic winter, Europe is facing a completely different, much warmer scenario, writes .
The polar vortex acts as an imaginary barrier during the winter, keeping the coldest Arctic air locked over the North Pole. However, with the arrival of spring and increasing sunshine in the polar regions, this vortex naturally weakens. Current data shows a sharp increase in pressure and temperature in the stratosphere (known as sudden stratospheric warming).
This warming, in which temperatures rise by 20°C above normal, causes a complete reversal of wind flow. The polar vortex is literally squashed and split into two separate cores – one heading over North America and the other over Siberia.
While a split core over North America pulls frigid air into Canada and the US, for Europe it means the exact opposite. The core of the polar vortex over the Americas helps form a large area of high air pressure directly over the old continent. Thanks to that in the next few days, an above-average warm air mass will expand. Freezing air will be pushed far to the north and east.
Thus, the first half of March in Europe will be in a clear trend of warmer and more stable weather. However, the development may change slightly depending on the final position of the second core of the polar vortex over Siberia. If it moved further west, it could push colder air masses closer to European borders.
Changes in the stratosphere are usually reflected in surface weather with a delay of 10 to 30 days. Long-term models (e.g. European ECMWF model) therefore indicate interesting developments for the second half of March. In mid-March, warm weather should continue to dominate, especially in Western, Central and Northern Europe. However, forecasts indicate that a “drop” of colder air may already appear further east.
At the end of March and the beginning of April we are already in the full window of stratospheric influences. Trends show that high pressure could return over the Greenland area. This would allow Atlantic lows to penetrate deeper into Europe, which would bring cooler, wetter oceanic air mass from the west and northwest, pushing the untimely warmth further east.
While Europe will enjoy the arrival of spring, the US (especially the north and northeast) and Canada will face widespread cold anomalies. Temperatures are expected to drop well below freezing and winter storms with strong winds are expected there, a direct result of the American core’s disintegrating polar vortex.
