Today we see great images from the Western Alps. In the Northwest Alps, it is snowing as far down as the Swiss alpine foreland. Meanwhile, it is also snowing in more and more places in the Southern and South-Eastern Alps. In the southern Alps, the snowline is still down into many valleys due to the cold air present, with snow in cities such as Meran, Bozen and Trento, for example. Milder air will flow in from the south-west, causing the snowline (especially at the edge of the Alps) to rise to about 1500 metres. Also in the Western Alps, we see that the snowline has risen, especially in the southern areas as expected with the supply of some milder air. Further east on the north side, it is stormy today especially higher up due to the föhn.
In the southern Alps, this snow will deliver around 10 to 20 centimetres, with most in the southern areas. In the Julian Alps, significantly more may also fall higher up. In the French Alps and western Switzerland, we will see accumulations of around 20 to 40 centimetres. Most of it from the Mont Blanc massif to the Écrins. Inner Alps in the Maurienne Valley a little less.
While the precipitation in the southern Alps quickly recedes, it could snow on the border of these two air masses in the north-western Alps for an extended period. Switzerland and the northernmost areas of the French Alps are still in the cold, keeping the snowline (well) below 1,000 metres. Going further south, we can already expect a rising snowline above 1,500 metres in Savoie and even a bit higher at the alpine edge. Exceptions, especially in the sheltered narrow valleys, are of course always possible.
Tomorrow, this precipitation will gradually spread over the rest of the northern and eastern Alps. Much more than 5 to 10 centimetres does not seem to be in the weather charts at first. The snowline will be around or just below 1,000 metres in the southeast, but down into the valleys on the north side. East of approximately Innsbruck, it may continue snowing longer into Sunday. Especially in Salzburgerland, Upper Austria and northern Styria, around 20 centimetres, with continued stau perhaps as much as 30 centimetres could fall. In the Western Alps, increasing high-pressure influence increasingly clears up over the weekend. In the process, it gets quite cold.
After the weekend, the Western Alps soon seem to be up for new snow. On Monday, a separate low pressure core detaches from a large low pressure system over the Atlantic and then heads eastwards towards the Western Alps. On Tuesday morning, we can expect the first precipitation in the French Alps. Initially, it is still very cold, but as the core is fairly warm, we will also see a rising snowline anyway. At the moment, around 20 to 40 centimetres are in store, locally maybe even a bit more.
The models still differ a little on what happens next. So don't take the snowfall amounts above too literally yet. In the American model, the Swiss north side could still get quite a bit of total precipitation, but after that the fun will be over. The Austrian areas (east of Vorarlberg) can still benefit from about 10 centimetres, but it won't be much. The ECMWF shows the low-pressure area moving even further east, resulting in a bit less snow in the Austrian Northern Alps on the back of the depression and then a (temporary) cold spell. During the passage of the low-pressure area just north of the Alps, the air pressure difference between the Northern and Southern Alps does increase to the extent that the Northern Alps could possibly face a serious föhnstorm.