Dry and sunny this week, but will winter return this weekend?


By Henri on 13 December 2021 · 0

A sun-drenched Zermatt today (riffelalp.com)
A sun-drenched Zermatt today (riffelalp.com)

After all the snow that has fallen, the Alps are looking forward to a number of sunny days this week. Only Austria will have to deal with some clouds for a little longer, but also there we will see more sunshine from tomorrow on. After a couple days with fairly mild and dry conditions, the weather models start to show a potential cold air outbreak for the Eastern Alps due to a strong northeastern flow during the upcoming weekend!

Snow this morning in Loser - Altaussee at an altitude of 1100 metres (panomax.com)
Snow this morning in Loser - Altaussee at an altitude of 1100 metres (panomax.com)
But as the warm front moved further in, the snowfall turned to rain up to about 1500 metres (panomax.com)
But as the warm front moved further in, the snowfall turned to rain up to about 1500 metres (panomax.com)

Sunny everywhere except the Eastern Alps

While large parts of the Alps are faced with a bright blue sky today, it was just a drizzly morning in Austria. Yesterday, the approaching warm front was already visible in the form of high clouds. In the evening and night, some precipitation moved in from the north. Due to the arrival of warmer air, the snowline rose considerably, especially in the northern areas, to around 1500 metres, while the snowline was somewhat lower in the inner alpine areas. Today, it cleared up more and more from the west in Austria as well. Everything east of Salzburg will remain in precipitation for a little longer.

High pressure directly above the Alps (wxcharts.com)
High pressure directly above the Alps (wxcharts.com)

High pressure weather

In the coming days, the Alps will have to deal with a dominant high-pressure area. The blocking high-pressure area ensures that all depressions pass far to the north of us, so we do not have to expect precipitation, but it will not be sunny everywhere. Especially on the northern side, the Alpine foreland has to deal with an inversion and thus low clouds that can only be cleared with great difficulty during the day. This is also the case in the valleys. Higher up in the Alps, however, it will often remain sunny due to the descending movements of the high-pressure area.

Tomorrow, some high clouds will pass over the Alps from the north, ensuring that we will have to deal with a more diffuse sunlight. The Western Alps are likely to stay completely sunny though. Wednesday and especially Thursday will be two beautiful days in the Alps with very mild temperatures for the time of year. The higher temperatures will allow the snow cover to settle slowly but surely, but nevertheless the avalanche risk will remain high, partly due to the widespread critical old-snow layer.

Jet stream directed towards Austria (meteociel.fr)
Jet stream directed towards Austria (meteociel.fr)

Cold from the northeast

Until Thursday, the core of the high-pressure area remains over the Alps, which means that the weather pattern will hardly change. On Friday, however, the core will shift further towards Great Britain, putting the Alps more on the eastern flank of the high-pressure area and allowing the jet stream to reach the Alps from an unusual angle. This setting ensures that, at least for the Eastern Alps, a north-easterly flow develops. This flow, with Russia and Finland as its source area, could bring icy conditions to the Eastern Alps by the weekend, and possibly even to the rest of the Alps.

But will there be snow? With this northeastern flow, Austria might also get some snow during the weekend. With this scenario I expect the most for the Salzburgerland to the extreme Eastern Alps, as also shown in our snow forecast. In combination with a strong wind, it could become really freezing cold. Due to the increasing pressure difference between the Northern and Southern Alps, this weather situation may simultaneously create a strong Nordföhn for the Southern Alps. From Thursday onwards, this Nordföhn will be felt in more and more places.

The north-eastern flow is transporting cold air masses to the Eastern Alps (wxcharts.com)
The north-eastern flow is transporting cold air masses to the Eastern Alps (wxcharts.com)

Also snow for Piedmont?

A region to keep an eye on is Piemonte. If the flow turns a bit to the east, the Piedmont might get some snowfall during the weekend. At the moment, not all models see this as a possibility, but small shifts in the model runs in the coming days could still make it happen. All in all, these are pretty interesting developments that I will be keeping a close eye on in the coming days.


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