The first dump is the sweetest, although hopefully not the deepest, because let's assume that, analogous to "the first cut is the deepest", the first dump will not also be the deepest. But you could say that the first real snowfall of the season is the one that causes the most excitement and anticipation, because it's finally starting properly. We've been waiting for weeks in November for the right weather conditions, last time there was no base and now it's here, the snow. At last! Winter is now beginning outside of the Ischglberg-Mountain Experience TM advertising brochures and special interest confectionery stands at Aldi.
So what does it look like? An Italian low brings snow. Where is it going? To France and the southern side of the Alps. For the time being. Whether a turning current from the passing low will then also bring something to the north from Thursday will be clarified on Wednesday, if necessary.
How does it work? In a first wave, a changing southwest / south / southeast current will establish itself today, which will already cause precipitation in France and especially in Ticino. This will be kept alive until Thursday morning by a small depression that is slowly moving south of the Alps and will continue to intensify until Wednesday, before causing precipitation north of the Alps from Thursday as the depression moves through.
Where will it snow and how much? This is the crux of the forecast, or the abseiling point of our little meteorological powder route, because different areas will be covered depending on the path of the train.
For sure, France will be well covered, south of the Hautes Alpes (approx. La Grave) down to the Maritime Alps with amounts of 50-70 cm, possibly up to one meter depending on the flow and location.
It will be difficult to forecast the areas of the Southern Alps including the French-Italian border region. According to the latest model developments, the whole area is divided into two main precipitation cores: one from the Simplon area via the Via Lattea down to Piedmont. And a second more towards the Dolomites. (Although I see the Dolomite core as a shaky candidate). In these regions, 70-100 cm are quite certain to be widespread and I see the limit at 120-150 cm in some congested areas.
Between eastern Ticino and the Ortler group, it's supposed to snow less, but 50-70 cm with a 20 cm margin upwards is also possible.
BUT! Depending on how the low moves, the eastern focal points of precipitation may still shift, so not everything is in the bag yet. As you know, Italian lows are as capricious as tax officials after changes in the law.
Snow line: The second sticking point, because the further east you go, the higher it will rain for a long time, while in France the snow line will drop to 1000 m on Tuesday and in eastern Italy below 2000 m by Wednesday, Ullr's first greeting is unlikely to happen.
In the Simplon region and other closed valleys, however, the snowfall may fall deeper than forecast, so that surprises are possible there early on. However, the snowfall in Switzerland also tends to start between 1600-1800 m and then decrease with heavier precipitation and / or the passage of the low pressure system.
So, I would take a look at the regions mentioned on Thursday/Friday, because with a probable wind shift to the north, you should be able to see Ullr's first greeting there. Keep lighting candles in the Ullr shrine and winter will be fine ;)
Powder to the people!