In an uncertain time in which we do not yet know whether we can travel to the Alps or if the lifts will be open, writing about the dominant high-pressure situation in recent weeks was actually not that bad at all. However, as the title suggests, we are on the eve of a winter raid for the Alps. On the last day of NOvember, the month where we saw hardly any snowfall, things suddenly look brighter from a meteorological point of view. It's going to dump! Precisely at the same time as the start of December, the weather over Central Europe will change and we are rid of the persistent high-pressure blockages. It is unfortunate that we cannot make use of it yet, but let's remain positive: the expected snowfall for next week can become a very nice base for the rest of the season, especially for the Southern Alps.
In this forecast:
Today will be the last day that the entire Alpine arc is dominated by high pressure, which means that we again have to deal with inversion weather in many Alpine valleys. Yesterday this inversion remained quite persistent (see satellite image), but today there is a greater chance that this low-stratus deck will release in the course of the afternoon. Above the inversion the air is very dry, making it another beautiful sun-drenched day in the high alpine with a freezing level of around 2000 meters.
Where the models Friday were not completely in agreement about the center of gravity of tomorrow's snowfall, it is clear today. The ECMWF was right and the Swiss Alps will benefit most from the temporary northwest current. It will not be very much, but with a dropping snow line that eventually reaches around 500 meters, about 10 to 20 centimeters of snow can fall on the Swiss north side of the Alps. To the east of Innsbruck, the amounts of precipitation will be negligible.
The recent developments on the weather maps are in line with the monthly forecast of the ECMWF, which already predicted a wet December for the Southern Alps in October. It seems that more and more low-pressure areas above the Mediterranean Sea and west of the Alps determine the weather picture, which means that there is a lot of snow in the forecast, especially for the Southern Alps.
The development of a Genoa-low will also provide snow for the Southern Alps tomorrow in the evening. It is again a hit for the south of the Piedmont. Here, about 20 to 30 centimeters of snow can fall with a snow line of around 500 meters. Carinthia, the Dolomites and especially the Julian Alps can expect up to 30 centimeters of snow on Wednesday and Thursday. There are still quite a few differences between the weather models, which does not make it any easier, but can provide surprises. For example, the GFS and ICON model show more snow for the Piedmont and the Julian Alps (up to about 50 centimeters), while Lombardy, on the other hand, doesn't have to expect more than 10 centimeters of fresh snow. The European model is still reasonably holding back when it comes to the amount of snow and will let the sun come out soon clear on Thursday.
The north side will remain sheltered from the snowfall after tomorrow. Especially the areas close to the main alpine ridge can still experience a lot of clouds and some flurries from the south, but the further north, the smaller the chances of snow. In the course of Thursday the chances of precipitation will decrease further and the southern Föhn will increase in strength.
In normal circumstances this would have been the first PowderAlert of the season, because it really seems to start from Friday. Under the influence of a strong depression over Great Britain, it starts to snow in the French Alps on the night from Thursday to Friday. I don't want to talk about precise details yet, because as indicated earlier, the amounts and timing of the snowfall on Wednesday and Thursday is also not 100% certain. Whether the north side will also benefit from the snowfall in the weekend as a result of a 'Gegenstromlage' is not yet certain, but the north side of Switzerland in particular may benefit temporarily on Saturday. The north side of Austria, on the other hand, remains dry and has to take a high chance of Föhn into account.
A separate low-pressure core descends to the Mediterranean Sea, creating a fierce southern current that pushes the moist air against the Southern Alps. In particular, the Eastern Southern Alps (Dolomites and Julian Alps), but also East Tyrol and Carinthia can look forward to more than half a meter of snow. While the American model holds back in predicting this snowfall, the ICON and ECWMF models take it a step further. It is therefore still too far away for the precise details. With the continuing southerly current, some warmer air will probably flow in on Saturday, causing the snow line to slowly rise.
We can't travel to the Alps, winter is still coming, but the preparation can already start! Whatever it will look like, the wePowder Guide is available again in the pre-order. For € 45.00 (excl. shipping) this thick book of 400+ pages will be delivered to you mid-December! Thanks for your support!