Current situation
First, let's take a look at the low from the last southerly storm and the current situation. We are in a large-scale low-pressure complex, the core of which is currently located at the southern tip of Scandinavia. The polar vortex is currently rather out of round. To the west and east of our low pressure system and the associated cold air, high pressure prevails far to the north with comparatively milder temperatures. A meridional situation in which the pressure centers are shifting only slowly. The Alps are in a southerly flow - anyone who has been out and about in the northern Alps in the last few days will have noticed something between a fresh southerly wind and a Föhnor gale, depending on the region. The air flowing in from the south is colder than you might expect from a südstau/north föhn, as the core of the steering low lies relatively far to the north. The air mass from the north does not penetrate far into the Mediterranean region and therefore cannot warm up very well there before it reaches us.
The amounts of fresh snow in the south were accordingly quite fluffy, but could not keep up with the record event of the last südstau in terms of quantities. Nevertheless, some stations set further records; in Lienz in East Tyrol, for example, December 2020 is now the snowiest winter month in recorded history. Another interesting fact: the low pressure was very low - in other words, it had an unusually low core pressure. The drop in pressure on the arrival of the low was correspondingly impressive, captured here in a video by MeteoSwiss. Take a look at the MeteoSwiss blog for more background information.
