The webcams showed us white mountains with PowderAlert #1b, but, as forecasted, it got warmer right after that. Will PowderAlert #1C be colder? The details were not quite sure yet a couple of days ago. But what's the status right now?
Why PowderAlert 1C?
Yes, snow will fall. It might snow a lot between Sunday and Tuesday (in the higher alpine). The snowline will drop temporarily to 900-1500 meters. So, what's the reason there's no second PowderAlert? Well, the temperature will rise rapidly after Tuesdays snowfall. The temperature is dropping below the yearly average between Sunday and Tuesday, but will rise again on Tuesday. This is caused by hot air coming in from the southwest, which pushes the snowline up to higher altitudes. The combination of a rising snowline, wet snow at high altitude and some wind is just not enough for a PowderAlert. But hey, if you're around anyway....
Cold air is coming in from the northwest on Sunday. The snowline will drop to 1000-1500 meters and it will snow a lot in the French northern Alps. The front will move to the east and the wind will turn northwest. This results in (lots of) snow in the Swiss northern alpine ridge, Vorarlberg and the Austrian main alpine ridge. The second front will arrive during the night of Monday to Tuesday. The snowline will drop again and it will snow a lot in the western Alps. The front is moving southwest after that and this causes the snowline to rise rapidly to around 2000 meters on Wednesday. The freezing level is even higher, on 2500-2900 meters. It's not really appealing, especially in combination with the warm wind. But if you're around anyway, you might enjoy some powder for a day or two.
According to the GSF we're not even close to a second PowderAlert and the Alps will be dominated by warm air for a while after Tuesday. The European ECMWF is more optimistic and sees some cold air coming in from the north after the 11th. In short: it will be winter form Sunday to Tuesday. It will be too warm after that and it might snow again after the 11th.