A cold front will bring some snow in the higher parts of the Alps today and overnight. Up to 30 centimeters of snow is possible in some higher-lying parts of the north-western Alps, but further to the east and south the amounts decrease rapidly. After the cold front, the sun returns and it becomes milder again. New snow may follow on Sunday, this time mainly on the southern side of the Alps.
Dump in the US
Unfortunately, the images above are not from the Alps, but from Mammoth Mountain (CA). Here, the first winter storm has hit home and provided a first serious powder day of the season. For the Alps, we still have to be a bit patient, but still, some snow could fall here too.
Precipitation grazes the Northwestern Alps
Especially in Haute-Savoie and the Swiss canton of Vaud, some 20 to 30 centimeters of snow may fall above 2500 meters today. This is due to a line of precipitation grazing the Alps this morning. In the unstable atmosphere west of Grenoble, we even see a thunderstorm cell. Only later in the afternoon and evening will the cold front move deeper into the Alps, so other areas will also catch some snow.
Cold front
The snowline will drop to around 2000 to 2200 meters during the day. The cold front will move further east during the day and evening, but will also weaken in the process. I do not expect much more than 10 centimeters of snow in the remaining northern areas. The snowline will be slightly lower further east with values between 1600 and 2000 meters though. In the southern Alps, it will also remain at a maximum of 5 to 10 centimeters above 2500 meters.
High pressure area takes control
Behind the cold front, increasing high pressure quickly clears things up again. Milder air masses are advected towards the Alps from the west. Especially the northern Alps will have to deal with these milder air masses in the following days. Fortunately, the Alps avoid the biggest heat, which is now calculated further north.
Snow in the southern Alps?
The new model runs for snow in Piedmont I mentioned on Monday have changed a bit. On Sunday, this (south-)easterly flow is indeed still possible, but whether it will deliver snow and especially where is still unclear. For now, one region seems to have good chances. The European model now calculates some snow on Sunday, especially for Ticino and surroundings. Around 10 centimeters above 1700 meters is possible here. Meanwhile, the American model also indicates some snow, especially for Ticino, but here, at the same time, a setting up south-westerly flow over southern France provides some snow in the French Alps. However, the ECMWF does not follow this scenario. Instead, the European model calculates a stronger föhn wind for the French Alps, which will suppress precipitation. On the northern side, the French Northern Alps and western Switzerland have the best chances to benefit from this snowfall.
Uncertainty increases
Forecasts for next week are still quite uncertain. Temperatures remain above average, but do seem to slowly creep back towards normal. Precipitation signals indicate that regular snow is also possible higher up, but the GFS main run is more pessimistic again today and thus quite dry.