The north-west Alps will receive a nice layer of fresh snow today. Above 2000 metres, a total of about 20 centimetres could fall on top of last days' snow in some regions, but the really interesting developments are for the possible south side dump after the weekend. The GFS now seems to be convinced, increasing the chances of a big dump in the southern Alps. Nevertheless, the details are still uncertain.
Before that, we also experienced snowfall in the Northwest Alps today. Initially, the snowline in the Western Alps was still quite high, but with the snowfall, significantly cooler air is also flowing in, so we already see the snowline dropping nicely in many places, to below 1500 metres. From the west, meanwhile, it is already clearing widely. I expect amounts of around 10 to 20, locally up to 30 centimetres in the Northwest Alps, from the French Northern Alps to Arlberg higher up. The snowline may drop further to around 1000 metres on the north side over the course of today.
Over the weekend, the Alps will keep it mostly dry. The really cold temperatures remain northeast of the Alps, but especially on the northern side of the Alps temperatures are still below zero at 1500 metres. On the border of two air masses, quite a bit of precipitation could fall over Germany over the weekend. It is possible that this boundary will touch the extreme northern Alps a little during the weekend, possibly resulting in some snow showers, but the vast majority of the Alps will just keep it dry.
From the northwest, precipitation follows again on Sunday evening, but the front seems to graze the Alps a bit more instead of hitting it. Much more than 5 to 10 centimetres in the north-western stau areas and along the north side will not be there. The snowline will be below 1000 metres due to the cold air present, though.
As I wrote in the last weather report, GFS still didn't really believe in the south side dump for after the weekend. While the European model was convinced for already several model runs, the American model was always a bit disappointing. Here, a decent southerly flow up to the Alps was not calculated, so all precipitation would end up further east.
What do the models show today? The GFS now seems to follow the pattern of the European model, where a lot of snow could start falling in the southern Alps! What's different? The core of the low pressure area follows a slightly more northerly route (north of Sardinia in the Gulf of Genoa) in the new model run, allowing the precipitation to reach the southern Alps as well. In the previous runs, the core was slightly too far south. At the same time, the European model is actually a bit more pessimistic compared to its previous runs, with markedly reduced snow amounts for the regions west of the Dolomites. Before we can talk about the details, we really need to wait for the new runs. An additional update on this snowfall will therefore follow over the weekend!
Now the focus is on the Alps, but let's also see what this weather situation is going to produce in the Pyrenees. After the weekend, the higher regions here too are going to get a thick layer of snow. It will be the base for the season on the northern side. However, the snowline here fluctuates quite a bit. In the additional update, I will also go into a bit more detail about the expected snowfall in the Pyrenees.