As happy as you are to have beer, you just don't enjoy stale beer. It's the same with this alarm. It may be snowing, but it quickly gets so warm that you can't enjoy it. First things first for all those who aren't afraid: there's probably a small window on Sunday morning where you might be able to ride the fresh snow for 3-4 hours, but more on that later.
What's happening?
After it's been unseasonably warm again for the last few days, some colder air with a westerly flow is coming towards us for a short time this evening and it's starting to snow. This alert is valid until Monday morning and the total amounts only above 2200m. There is an extra alert for Sunday morning.
Where is it snowing?
Once again, the most snow is expected from Savoy to the Arlberg, with the hotspot actually being on the Arlberg and not in the west. However, this time it is also expected to snow in alarming quantities as far east as Salzburg / Upper Austria.
How high is the snow line?
Well, Ullr has set me a task, because at the beginning of tonight it's 1200-1400m in France, 1000m on the Arlberg and below 1000m in eastern Austria. Then it rises rapidly and by midday on Sunday it's 1700-1900m in the west, 1300-1500m in north-eastern Switzerland / Arlberg and around 1000m in the east. These should be the limits where you can still ski the fresh snow. Glop TM may also fall a little lower. By the evening it'll be down to 2000m+ in the west and around 1500m in the east. Monday will be dry but with a zero degree limit beyond 2500m.
How much stale beer will Ullr be serving?
Good question. Since the whole thing will be warm, with a front and little congestion, I assume 30-50cm in northern France up to the Arlberg, possibly 60-70cm somewhere far up in a west congestion hole. In my opinion, however, a maximum of 50cm is more realistic in this constellation. Further east, I'm not sure if that's not further down, but 20-40cm should come. With the incoming flow, however, I would rather expect surprises down in the east, so I would say 15-30cm is more likely.
What's the forecast for Sunday?
It will snow all day and the snow line will creep upwards. By the morning, 20-35cm should have fallen from France to the Arlberg, which you might be able to ride for 3-4 hours before it gets too warm in the trees.
Where should I go?
All people who are inclined to gamble should go somewhere in north-eastern Switzerland or towards Vorarlberg very early on Sunday and wait for the rain, which will probably start by midday at the latest. Or hope that it stays low for longer in the east. But not much will fall there until the morning. Everyone else should go out really high (2500m+) on Monday and see if the total amounts have arrived.
So watch out for the warming on Sunday and on Monday further up on the lousy old snow cover. It's not looking great in the medium term, but not horrible either. Neither fish nor fowl. Nevertheless: Powderglop to the people! Your oracle