With a few days to go, the exceptionally warm October 2022 will most likely go into the record books for parts of the Alps. On a large scale, especially higher up in the mountains, October was even warmer than September. Over the next few days, it will be persistently mild with a freezing level around 3500 metres. After the turn of the month, however, we seem to slowly approach winter with possibly some snow chances and temperatures a bit more normal for the time of year.
October ends with once again temperatures well above 20 degrees in the valleys (locally up to 25 degrees) and a particularly mild south-westerly flow higher up. With a freezing level just below 4000 metres, it feels almost like summer. Only the early sunset and autumn colours reveal that it is no longer summer.
The cause of these exceptionally high temperatures is a strong south-westerly flow that ensures the supply of very mild air. The strong south-westerly flow will also transport another portion of Sahara dust towards the Alps. In the coming days, visibility may be somewhat reduced in the lower air layers. Higher up, Sahara dust concentrations will remain limited, meaning that there will most likely be little additional cloud cover.
For a while now, weather models have been hinting at a weather change from the start of the new month. As the south-westerly flow weakens, we will gradually move towards temperatures that are normal for the time of year. Whether it is associated with (much) precipitation, however, remains to be seen.
From Tuesday onwards, the jet stream moves into a more zonal pattern (west-east) which allows depressions to reach the Alps better and are no longer held back by the blocking high-pressure area over Europe. By the middle of next week, this could bring some precipitation, especially for the Western Alps, but exactly how much will fall is still very uncertain at the moment. A connection between the Azores High and the high-pressure area over Eastern Europe could still cause precipitation to be blocked. Depressions will then again follow a northerly route and miss the Alps. More on this development on Monday.
After a short changeable phase, some model runs are already hinting at a more or less similar pattern as the past few days in the Alps with a mild south-westerly flow, fortunately this development is also quite uncertain. One thing we can say is that there is no sign yet of a cold outbreak with lots of snow, but at least the first step towards winter is now being made with temperatures back around normal values for the time of year by the middle of next week.