After a long period of high pressure in October, November starts off with some amazing weather charts. The Alps will enter a much cooler and more changeable phase starting today. For the higher regions, this snowfall will probably be the first base for the season.
In this weather report:
- Today and tomorrow 20 to 30 centimetres of snow on a large scale
- From Wednesday a second wave with a lot of snow
- After that: changeable in the southern Alps, dry in the northern Alps
Cold front brings cooling and fresh snow
^The forecasts on wePowder are powdered by our friends at Ortovox
The DWD (Deutscher Wetterdienst) analysis map above clearly shows that the precipitation that is currently falling is due to the passage of a cold front from west to east over the Alps. Ahead of the cold front, Austria had some föhn this morning, but also here the cold front will pass from west to east in the course of the afternoon and evening. This morning’s satellite image shows the cold front very well. The dense cloud cover and precipitation in the southern Alps due to a small low pressure area over Genoa is also clearly visible. On the ground it looks like this:
The snow line is already dropping nicely below 1500 metres in some places due to the heavy precipitation. In the Western Alps, 20 to 30 centimetres are possible until tomorrow. In the Southern Alps I expect similar values of 10 to 30 centimetres. Further to the east (Julian Alps, Eastern Dolomites) more precipitation could easily fall (locally up to 100mm precipitation), but here they have to deal with a pretty high snow line due to the warmer air from the Adriatic Sea.
In the coming hours, the precipitation will also reach further east. At the moment it is still dry and mild in the extreme Eastern Alps (as shown on the webcam image of the Turracherhöhe), but from tonight it will start snowing here as well. The föhn in Austria will be over and I expect a total of 20 to 30 centimeters of snow (locally even more) with a decreasing snowline. Especially on the north side of Austria, the snowline might temporarily reach 1000 meters. In most places it will probably snow from about 1500 meters.
Temporary clearing
Tomorrow, the Alps will temporarily be under a weak high pressure influence, which will make it possible for it to clear up everywhere. The Northwest Alps in particular will have to deal with snow showers during the day. This quiet phase won’t last long, because in the night from tomorrow to Wednesday a new low pressure area will approach, which will bring quite some snow for the Alps again.
Vb-Wetterlage
On Wednesday and Thursday, again, a lot of snow will fall in the Alps. The reason for the snowfall is the so-called “Vb-Wetterlage” (Five-b Weather Situation), where a low pressure area over the Mediterranean Sea moves over the Alps to the northeast (yellow line). The first precipitation is mainly for the western and southern Alps, but due to the route the low-pressure core takes, the northern Alps are next in line.
On the western flank of this low pressure area, cold air from the north can be brought to the Alps (blue arrow). This explains why our snow map for Thursday even shows snow up to the German Alpine foreland, while the snowline further east is higher. Note that in the coming days this boundary between cold and milder air may shift a bit.
In the Western Alps, another 10 to 20 centimetres of snow is possible. In the southern Alps, a large scale of half a meter of snow is possible according to several weather models with a snowline around 1800 to 2000 meters. The Eastern Alps will again have to deal with a lot more precipitation, but a higher snowline (2000 to 2500 metres). While it will remain dry in the Northern Alps on Wednesday (apart from the areas around the Alpine main ridge), it could snow quite heavily on Thursday. The exact amounts in the Northern Alps are still hard to determine, though.
More snow for the Southern Alps?
It seems that the weather in the Southern Alps will continue to be changeable after Friday. In the ensemble of the American GFS model for Trento above, in addition to the two strong precipitation peaks this week, you also see a precipitation signal early next week with a higher snow line. On the northern side (Geneva area) it will most likely stay dry for a few days after Thursday.