The very mild air has left the Alps and many regions are still waiting for their first real dump. Only the French and Swiss Alps have a reasonable base above around 2000 meters. A depression moving over the Netherlands today will cut off as an upper-level low and will be near Greece by Friday. On the backside of this system, it will snow for some time in the Northern Alps on Thursday. Over the weekend, a high-pressure area will dominate over the Alps, making it dry and sunnier
Mild and dry afternoon
This morning, an area with light rain (and snow above 1400-1800 meters) over Carinthia and Slovenia will move eastward. After that, a dry and calm day will follow throughout the entire Alpine region. It is mild with a freezing level around 2000 meters and wide clear spells.
Thursday brings 25 centimeters of snow regionally
It will become cloudy overnight and by Thursday morning the first precipitation will start falling in Switzerland and Vorarlberg. The snow line will initially be around 1700 meters but during the day it will drop to about 1000 meters behind the cold front. The precipitation will then reach a large part of Austria and Switzerland. Most snow is expected in a strip from West Tyrol to the Central Swiss Alps, 15-25 centimeters. Below 1500 meters, it will mainly rain but in the tail end of the precipitation area, it can still turn white for a while. The Northern French Alps can also pick up a few centimeters of snow above 1500 meters in this tail end. On the north side of the main ridge, a strong northwesterly wind will blow with gusts of 60 km/h. On the night to Friday, it will clear up widely but a snow shower from the north can still drift into Salzburg, Styria, and Upper Austria. Light frost will occur down to most valleys.
Weekend with high pressure
It seems to be a trend this autumn as the dry and sunny weather again occurs during the weekend. A strong extension (1030 hPa over the Alps) of a high-pressure area over Eastern Europe ensures stable weather. On Friday, the eastern half of Austria will still have some clouds, elsewhere it will be mostly sunny. Over the weekend, these clear skies will be found throughout the entire Alpine region. Inner Alpine regions in Austria and the Southern Alps will remain the coldest under the influence of the previously mentioned cold pool, with night frost at all levels and a freezing level around 1500 meters during the day, especially on Friday and Saturday. In the Northern and Western Alps, the freezing level is around 2000 meters, and from Sunday it will also warm up to these values elsewhere in the Alps.
New snow events possible from Tuesday onwards
The mild weather on Monday seems to give way to a colder air mass from the north by Tuesday. This is due to a weak high-pressure ridge over the British Isles, temporarily causing a northwesterly flow. The freezing level will drop back to around 1500 meters on Tuesday and Wednesday. Additionally, precipitation is expected again, with weather models showing a preference for the French Alps. This can still change at this range, so keep an eye on WePowder for updates.
Weather possibly remaining changeable
In the long term, we see persistent precipitation signals in the forecast. In this scenario, there is an active westerly circulation where depressions follow each other and precipitation areas regularly move over the Alps. With a westerly flow, most precipitation is then expected in the Western Alps. This is clearly visible in the GFS ensemble forecast for Grenoble above. The temperature and thus the snow line fluctuates (mild at the front of disturbances, temporarily colder behind) and precipitation falls almost daily. Especially above 1500-2000 meters, this is a potentially snow-rich setting
