PA#11: Temporary comeback of winter!

As I wrote on Wednesday, a lot of snow is going to fall in the Alps over the next few days. Time for PA#11, but there are still some comments to be discussed: the snowline is initially quite high and it is going to be quite windy, especially during the weekend!

In this weather report:

• Cold front reaches northwest Alps
• Stormy westerly flow
• Low pressure area with snow approaches on Sunday
• Temporary comeback of winter
• Where to go?
• Then warmer

Cold front has reached the northwest Alps

The first cold front has now reached the northwest Alps with even some thunder embedded. It is not yet accompanied by a huge cooling, but the main heat is being expelled. The snowline is still around 2000-2200 metres in most places, but will drop towards 1500 metres during the evening. So the first snowfall is only for the high mountains, though.

Below we see the expected snow amounts until tomorrow morning. Especially in the French Northern Alps around the Mont Blanc massif and in Unterwallis amounts of around 30 to 40 centimetres, but as mentioned, these amounts will only be for >2500 metres. Significantly less falls in the other areas in Switzerland, here it will remain at up to 20 centimetres higher up. Inneralpine and in Austria even less.

Stormy western flow

Strong winds in the north-west Alps already caused many closed lifts today, but also during the weekend the westerly flow remains very strong, also in the northern Alps. So be aware that it’s very likely that higher lifts will also close in the coming days.

Tomorrow during the day, the Northern Alps (from Haute-Savoie to Austria) will experience showers. Snow will fall above 1300 to 1500 metres. In the more inner-Alpine areas, the sun may also get a chance to show itself in between, especially in Austria. Here, it is mainly the northern areas that will experience showers. In the evening, shower activity decreases everywhere. In the western Alps, it will then remain dry until Sunday morning. On the northern side, some snow may still fall in the northern areas during the night on Sunday. In Austria, it then remains dry until Sunday afternoon. With light föhn, precipitation is still suppressed. Meanwhile, it starts snowing again in the north-west Alps on Sunday morning.

Low pressure area with snow approaches Sunday

Things get really interesting from Sunday, as a low-pressure core moves straight towards the Alps, resulting in several precipitation phases. So on Sunday morning, the first precipitation follows for the Northwest Alps. Here it snows during the day from around 1,300 metres. In the evening, even cooler air flows in, allowing the snowline to drop below 1,000 metres. Again, I expect most snow in the French Northern Alps and Valais. Some 30 to possibly 40 centimetres of snow could fall higher up here.

During the day, the precipitation moves further eastwards. Until Sunday evening, the amounts will initially remain limited, but Sunday evening it will also start to snow heavily here. This precipitation will also reach the Southeast Alps a little later, but here the snowline will initially be a bit higher. Here, too, it cools off in the evening and night on Monday.

Flow turns north

During the night from Sunday to Monday, the flow turns north, allowing colder air to reach the Alps, temporarily creating a Nordstaus situation. Snow will fall from around 600 to 800 metres, temporarily also into the lowest valleys. Along the entire north side, and of course especially in the northern stau areas, the amounts could be quite high. I expect the most from central Switzerland to the Arlberg. Locally, half a metre of snow could fall. Snow is also falling in the French Northern Alps with a snowline below 1,000 metres, but the intensity here does decrease during the afternoon due to increasing high pressure from the west.

Where to go?

So where to go is quite tricky due to the strong winds over the weekend. Saturday is for most locations still too early, as in the Western Alps the greatest amount of snow has only fallen in the high mountains. So, should the wind be a bit less strong as expected, some powder can already be found around for example the Mont Blanc massif (French Northern Alps & Valais). This is also true for Sunday with snowfall setting in again and a lower snowline, but with strong winds in the morning it is doubtful how many lifts will open in the ski areas.

The focus is on Monday and Tuesday. These will undoubtedly be the best days. Monday with still heavy snowfall in the Northern Alps and Tuesday with room for sunshine in more and more places. Think of areas like Arlberg and Engelberg, where half a metre of snow could fall with a low snowline. Note that the northerly flow will remain strong. Of course, check avalanche bulletins before heading out as well. Of course, it remains to be careful with fresh snow combined with wind and a persistent old snow problem.

Then warmer

On Tuesday, we already see it getting significantly warmer in the Western Alps with temperatures at 1500 metres just above zero degrees. Also with the strength of the sun late March, the fresh snow will soon become heavy again. On Wednesday, it will also get significantly warmer in the rest of the Alps. On Thursday, with around 10 degrees at 1500 metres, it will just be full of spring weather again. So, with the exception of steeper shadow slopes, the powder will soon be gone again.

Read also:

• What is a Sudden Stratospheric Warming?
• 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 a retour d’Est?
• What is the jet stream?