WeatherBlog 14 2022/23 | Is winter coming back?

The WEATHER SITUATION AND ITS OUTLOOK

We start with the old story of this winter: snow conditions are well below average almost throughout the Alps, there has just been a long phase of stable high pressure and the rare PowderAlerts have often been blown away by the wind. But at least the high pressure is over for now. A low pressure system over Scandinavia will send a deep trough to the northern slopes of the Alps towards Saturday. There will be a lot of fresh snow and a considerable drop in temperatures. The low moves further east but the trough remains for a few days and continues to bring cold air from the north-east to the Alps. A high-pressure trough detaches from it and becomes weather-determining for the Mediterranean. What is very surprising is that this low-pressure system continues to move westwards into the Atlantic. This could bring some more snow to the south side of the Alps and the Pyrenees.

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Webcam of the Mont Fort in Verbier: the Bec des Rosses on the far left

Influence from the stratosphere

Far above our weather patterns, in the stratosphere, a Polar Vortex Breakdown and subsequent Sudden Stratospheric Warming has been taking place in recent weeks. This means that the prevailing cyclonic circulation is destabilizing and weakening due to vertically propagating and breaking waves, which is accompanied by warming. Within a few weeks, the circulation moves further and further towards the troposphere and then exerts an increasing influence on the jet stream, undulating it and allowing cold air intrusions to occur more frequently. On a statistical average over many events, there is even a signal of increased precipitation in the Alpine region. The ECMWF seasonal forecast also gives hope for snow in March and a conciliatory end to the winter. The current general weather situation could certainly be seen as a small sign of a return of winter.

Cold air arrives. Geopotential height at 500 hPa and air temperature at 850 hPa, from left to right: Tuesday, Friday and Tuesday next week.

Snow conditions and water supply

You could even hear the fears of the Trentino authorities on the news. The low snow levels will also have a considerable impact on the water supply in summer. After the record drought last summer, people are certainly sensitized and water savings could be the result. We can only hope for a March with plenty of precipitation so that sufficient water is available for agriculture in the summer. Finally, the FWT would also be pleased to see a little more snow on the slopes of Wildseeloder and Bec des Rosses. The Polar Vortex Breakdown described above doesn't promise anything concrete for the time being, but at least it allows for surprises.