The Indian Summer in the Alps will end temporarily after the weekend. A strong northern current starts between a powerful high pressure area above the British Isles and a storm depression over Scandinavia. This current transports cold air from the polar region towards the Alps.
The +20 degrees celcius of today (Friday) in the Alps will not be reached in the coming days. Colder but drier air flows into the Alps on Saturday. There will also be fronts coming in between Monday and Tuesday that will bering some snow on the northern side of the Alps. Especially on Monday, the temperature can drop considerably with a snow line that drops to 700-1000 meters and even lower locally in the east of Switzerland and the north of Austria. All models calculate snowfall for Monday/Tuesday.
Check out our snow maps, WRF and ECMWF below. Side note. Our snow map is from Thursday. I expect the colors to become less intense today.
It is now less than 72 hours until the snow will fall, all models calculate snow and the northern current is dominant on all models. That snow is going to fall is certain, the quantities are still shifting a bit. The quick approach of the high pressure area above the British Islands can push the center of gravity of the precipitation further to the east. That's basically the biggest uncertainty, but I definitely expect to show some white images from the Alps on Monday and/or Tuesday.
Snow in this period of the year is not uncommon for the mid and high alpine. There's snow coming down in September on a regular basis. But it won't last till winter. The sun is just too strong and is still high in the sky. The temperature in the upper air layers are simply too warm as well. Anyway, the snow that will drop on Monday and Tuesday is great for the glacier resorts that will welcome many guests in the coming weeks. For us freeriders it is no more than a sign that winter is on its way.
Stay stoked, Morris