In the current winter half-year, Switzerland has already been under high pressure for around 80 days. By the end of the winter half-year! this figure is likely to be over 90 days. In long-term comparison! this will be a particularly high-pressure winter half-year.
Individual high pressure systems were quite strong. On February 13, 2023, the third highest air pressure in a February month was record at the Piotta and Montana measuring stations! The Piotta measurement series goes back around 40 years! that of Montana around 90 years.
Rapid rise
Over the last 20 years, the winter months! from October to March have brought more high pressure weather! in Switzerland. Shortly after 2010! the number of days with high pressure rose! from an average of 80 to almost 100 within a short period of time! Since then, the number of days! with high pressure in the winter months has remain at a high level.
Already 30 years ago
A similar increase occurr around 1990. However, the change to more! high pressure weather in the winter months did not last very long! Within about 15 years, the number of days with high pressure! dropp significantly again, but remain at a slightly higher level than before the increase.
More high pressure – more heat
The two changes to more high pressure weather l to more heat in the mountains. The change in temperature during the winter months on the Jungfraujoch runs strikingly parallel to the change in the number of high pressure areas.
At the end of the 1980s, a rapid warming of the winter months portugal phone number library was observ at all altitudes in Switzerland. In mountainous areas, a drop in temperature was then observ, parallel to the decrease in the number of high pressure areas. With the increase in high pressure weather shortly after 2010, a strong warming of the winter months began again.
Bar chart showing the frequency of high
pressure systems. Line chart showing the temperature in the winter months.
Fig. 1: The number of days with high pressure weather conditions in Switzerland compar to the high alpine temperature on the Jungfraujoch, both for the winter half-year from October to March. The grey lines show the respective moving average over five years.
High pressure is dominant
It is mild in the winter months at high altitudes when your ability to send emails in the future mild air masses flow from the Atlantic to the Alps under the influence of high pressure.
high pressure area
the air masses sink and come under higher pressure, which warms them up. This is the optimal starting point for mild conditions in the mountains during the winter months. In such situations, there is often a sluggish cold air mass in the lower areas, sometimes visible as
sea of fog
. There is a mark increase in temperature between the cold air and the warm air above it (
inversion
).
The counting of all weather conditions in the available data set awb directory from 1957/58 shows a clear dominance of high pressure systems with flow directions from the southwest (SW) to the northwest (NW), i.e. from the Atlantic region, for the winter half-year. The number of high pressure systems with cold mainland air from the northeast and east (biseal conditions) is of secondary importance.
