Chances for a dump in the southern Alps are rising, but details still uncertain

By Henri on 18 November 2022 · 8

The north-west Alps will receive a nice layer of fresh snow today. Above 2000 metres, a total of about 20 centimetres could fall on top of last days' snow in some regions, but the really interesting developments are for the possible south side dump after the weekend. The GFS now seems to be convinced, increasing the chances of a big dump in the southern Alps. Nevertheless, the details are still uncertain.

Snow from the northwest today

Before that, we also experienced snowfall in the Northwest Alps today. Initially, the snowline in the Western Alps was still quite high, but with the snowfall, significantly cooler air is also flowing in, so we already see the snowline dropping nicely in many places, to below 1500 metres. From the west, meanwhile, it is already clearing widely. I expect amounts of around 10 to 20, locally up to 30 centimetres in the Northwest Alps, from the French Northern Alps to Arlberg higher up. The snowline may drop further to around 1000 metres on the north side over the course of today.

Weekend mostly dry

Over the weekend, the Alps will keep it mostly dry. The really cold temperatures remain northeast of the Alps, but especially on the northern side of the Alps temperatures are still below zero at 1500 metres. On the border of two air masses, quite a bit of precipitation could fall over Germany over the weekend. It is possible that this boundary will touch the extreme northern Alps a little during the weekend, possibly resulting in some snow showers, but the vast majority of the Alps will just keep it dry.

From the northwest, precipitation follows again on Sunday evening, but the front seems to graze the Alps a bit more instead of hitting it. Much more than 5 to 10 centimetres in the north-western stau areas and along the north side will not be there. The snowline will be below 1000 metres due to the cold air present, though.

Lots of snow for the southern side?

As I wrote in the last weather report, GFS still didn't really believe in the south side dump for after the weekend. While the European model was convinced for already several model runs, the American model was always a bit disappointing. Here, a decent southerly flow up to the Alps was not calculated, so all precipitation would end up further east.

What do the models show today? The GFS now seems to follow the pattern of the European model, where a lot of snow could start falling in the southern Alps! What's different? The core of the low pressure area follows a slightly more northerly route (north of Sardinia in the Gulf of Genoa) in the new model run, allowing the precipitation to reach the southern Alps as well. In the previous runs, the core was slightly too far south. At the same time, the European model is actually a bit more pessimistic compared to its previous runs, with markedly reduced snow amounts for the regions west of the Dolomites. Before we can talk about the details, we really need to wait for the new runs. An additional update on this snowfall will therefore follow over the weekend!

Pyrenees

Now the focus is on the Alps, but let's also see what this weather situation is going to produce in the Pyrenees. After the weekend, the higher regions here too are going to get a thick layer of snow. It will be the base for the season on the northern side. However, the snowline here fluctuates quite a bit. In the additional update, I will also go into a bit more detail about the expected snowfall in the Pyrenees.

Want to read more about weather?

• What is an ensemble forecast?
• What are low- and high pressure areas?
• What is a northstau/nordstau?
• What is a southstau/südstau?
• What is föhn?
• What is the jet stream?

Comments

• 
  GavinSerreChe op 18 November 2022 · 16:08

  Don't think it's going to happen Matey....
  
  What was there is slowly disappearing, think we'll be lucky to see 10cm in the Valley here La Salle Les Alpes, Serre Chevalier by Tuesday morning, and I think that's being optimistic, but there again I suppose it depends on what ones definition of a dump is 😃
  Anyway you can what's actually happening on our DumpCam in on our terrace which on Monday and Tuesday will be panning around the terrace and the poles
  https://stylealtitude.com/serrechevalierweathercam.html...
  *message edited by GavinSerreChe op 18 Nov 2022 16:09
• 

  Beginner
  Henri op 18 November 2022 · 19:28

  Yup, it definitely won't be a full dump for the whole southern Alps, as you can also see in our forecast. The potential was there, but it's shifting more and more to the east. The new GFS 12z run is also showing less in the southwestern Alps/Piedmont/Ticino, the snowfall is more confined to Northeast-Italy. Also the new run (12z) of the ECMWF is quite dissapointing to be honest...
  *message edited by Henri op 18 Nov 2022 19:31 (1% bewerkt)
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  Expert
  Chester_Tartsnatcher op 20 November 2022 · 19:10

  Hopefully, this forecast has some merit:
  
  https://www.netweather.tv/charts-and-data/jetstream... .
  
  If so, end of November and start of December should bring snow and cold.
• 

  Beginner
  juancarlosdominguezlemoine op 20 November 2022 · 20:45

  As in the last 9 years or so, the snow is at the other side of the pond. if the climate wants to save itself better it changes its habits of sending cold to America. othersise there will be a lot of Americans denaying climate change.
• 

  Beginner
  Henri op 20 November 2022 · 20:48

  **Short update**
  
  Last weekend I kept an eye on the models, but ran out of time for an update. Despite some nice and hopeful charts, I was not convinced, because the differences were simply too big and previous runs already showed that it would take very little to keep the party from going through for the most part. Even this weekend, the models still differed quite a bit for Tuesday's snowfall. We see both GFS and ECMWF calculating the most for the Carnic and Julian Alps. Areas such as Nassfeld and Sella Nevea may get a seasonal base with around 50 centimetres of snow above 1200 - 1400 metres according to ECMWF, but meanwhile GFS does not follow. Here the amounts have been sharply scaled down. The GFS main run, however, does sit fairly low in the ensemble the past few runs and is therefore possibly a little too pessimistic. Meanwhile, the new runs also show big differences for the glacier areas of Austria, with 30 to maybe 50 centimetres for the Kitzsteinhorn and Mölltaler Gletscher, among others, according to ECMWF, but up to around 10 centimetres according to GFS... Tomorrow morning in the regular weather report hopefully then really finally some more clarity....
• 

  Beginner
  Henri op 20 November 2022 · 20:54

  Hopefully, this forecast has some merit:
  
  https://www.netweather.tv/charts-and-data/jetstream... .
  
  If so, end of November and start of December should bring snow and cold.Chester_Tartsnatcher op 20 Nov 2022 19:10
  
  Interesting, but I'm not so convinced by this chart at the moment. It looks like we're getting back to some more southwesterlies with higher temperatures in the Western Alps and slightly lower in the Eastern Alps end of November. By the end of the run it could definitely bring snow, but the beginning of December is just too far for these details. But we're definitely keeping an eye on these developments! Let's cross our fingers!
• 

  Expert
  Chester_Tartsnatcher op 21 November 2022 · 00:37

  As in the last 9 years or so, the snow is at the other side of the pond. if the climate wants to save itself better it changes its habits of sending cold to America. othersise there will be a lot of Americans denaying climate change. juancarlosdominguezlemoine op 20 Nov 2022 20:45
  This is the worst kind of disinformation. If you understood anything about Americans, you would know that the facts don't matter.
  
  😉
• 

  Expert
  Chester_Tartsnatcher op 21 November 2022 · 00:40

  
  
  Interesting, but I'm not so convinced by this chart at the moment. It looks like we're getting back to some more southwesterlies with higher temperatures in the Western Alps and slightly lower in the Eastern Alps end of November. By the end of the run it could definitely bring snow, but the beginning of December is just too far for these details. But we're definitely keeping an eye on these developments! Let's cross our fingers!Henri op 20 Nov 2022 20:54
  
  Agreed, it's far out (in the wrong sense). But I'll hope and cross every appendage I can.
  EuroBBI2023 Rueras !
  *message edited by Chester_Tartsnatcher op 21 Nov 2022 01:32 (16% bewerkt)

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