Once again, with a western circulation, a number of stormy days are in store for the Alps. In the process, quite a bit of snow could again fall in the north-west Alps. The snowline will be (very) high in the coming days! Only from the weekend onwards, the lower areas will also get some and it will most probably be time for PA#12. Today a description of the turbulent run-up to the new Powder Alert, in an update later more on the details for the PA#12 over the weekend.
Warm front today with some Saharan dust
A warm front moves over the Alps from the west today, bringing some precipitation on the north side. The somewhat higher concentration of sahara dust in the air (today in the Western Alps, tomorrow morning in the Eastern Alps) may also cause some additional dense cloud cover and reduced visibility, but otherwise the impact is likely to remain limited.
In Austria, the warm front was initially still accompanied by a snowline down into the valleys due to the cold present, but warmer air has already been brought in from the west, causing the snowline to rapidly rise. Indeed, in the north-west Alps, the snowline is already around 2,000 metres. In the afternoon, some showers are even possible in the French Northern Alps and western Switzerland, with the snowline rising to just below 2,500 metres. Not much falls, by the way. From Valais to Vorarlberg about 5 to 10 centimetres for the higher regions, due to the warm front also in the inner-alpine areas.
Thursday more precipitation
More showers will follow in the warm sector tomorrow morning, but a cold front will follow in the afternoon. In the process, it also cools down again, but it is far from a strong cooling. The snowline will stick from around 2,200 metres in the morning to around 1,800 to 2,000 metres in the afternoon. I also expect these values tomorrow in Austria. Once again, some 5 to 10 centimetres of snow could fall along the entire northern side above, from Haute-Savoie to eastern Austria.
Turbulent Friday
After a fairly dry night, another turbulent day awaits us on Friday. Already in the night to Friday, a pressure gradient develops over the Alps due to an approaching depression, which will temporarily create a föhn situation in the Northern Alps, but soon after that a new front follows from the west. With the passage of the front, the winds in the Western and Northern Alps pick up considerably, which is guaranteed to have an impact on the higher lifts in ski resorts on Friday, as well as the avalanche danger with the formation of wind slabs of course.
The snowline will slightly drop from around 2,000 metres to 1,500 to 1,800 metres during the snowfall. Above 2000 metres, serious amounts may fall as it will continue to snow in the north-west Alps in the form of showers after the front passes. In the French Northern Alps and western Switzerland, 20 to 40 centimetres of snow is possible on Friday, locally more is even possible. Further east, 10 to 30 centimetres seems to be in it on a large scale. As mentioned, this does come with stormy winds and initially a high snowline. During the evening, significantly colder air will flow in, though!
Flow turns northwest - PA#12 for the weekend!
This is because the flow is turning a bit more to the northwest, allowing colder air to flow in. Therefore, during the night to Saturday and Saturday during the day, the snowline could reach about 1,200 metres. The wind will moderate again (but will still be strong on Saturday!) and another 30 to 40 centimetres could just fall in the Northwest Alps, making it time for a new Powder Alert. All info on the new Powder Alert will follow in a new update.
While the spring warmth returned immediately after PA#11, it will now likely stay cold in the Northern Alps for a longer period after the snowfall of upcoming weekend. With a more northeasterly flow, cold continental air will be transported to the Alps, from which Austria in particular looks set to benefit for a few days.
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Replies
Saharan dust was very evident at Flaine today, just a few cms under the top dusting. Some decent snow up high, but very warm and it was slushy below 2000m. Looking forward to PA #12, Merci Henri!
Hello, just returning from Arlberg/Stuben. Yesterday we hiked in 60 cm of fluffy pow pow. Today rain in the valley. Thanks for your forecast wepowder. Looking forward to PA 12. Cheers.
Adam