Current situation
For more than a week now, a blocking high has been sitting firmly over the British Isles and is responsible for the sunshine we have been enjoying in the mountains over the last few days. The subtropical air mass that moved over the Alps with a light breeze from the north ensured warm temperatures, especially at higher altitudes. As the weather situation was fairly calm due to the weak synoptic forcing, persistent inversions formed in the valleys. These could be clearly observed at the weekend in many Alpine valleys due to the high fog. In general, the temperature in the atmosphere decreases with altitude. During such events, however, the temperature gradient reverses, hence the term inversion.
On clear nights, the ground radiates heat particularly well through long-wave radiation. As a result, the air near the ground cools down considerably and collects in the valleys as it has a higher density. However, as cooler air can also hold less moisture, fog forms, which is "capped" by the warm, dry air masses of the high pressure influence. In combination with the calm weather conditions, there is no mixing of these air masses, so that you can enjoy the view of a sea of clouds on the mountains. It takes the passage of a front, i.e. a synoptic forcing, to trigger the fog and the situation. So let's see if there is a change in the situation in the forecasts.
