ThoseHot air from the Sahara
Glutofen Switzerland: Why it is currently hardly cooling even at night
Switzerland has had the hottest day of the year. The subtropical air mass in slightly increased mountain lanks provided a special phenomenon.
The subtropical “broth” also ensures warm temperatures at night: the evening sky over Zurich from the polyter terrace.
Photo: URS power
- On Wednesday, the highest temperature of the summer was measured in Payerne at 36.5 degrees.
- Sahara dust dampened the sun’s rays and thus the maximum values in the Alpine region.
- On the Bantiger and the Uetliberg, the thermometer did not drop below 25 degrees at night.
- The heat wave lasts until the weekend, but the thunderstorm is increasing.
On Wednesday, the highest temperatures of this summer were measured in Switzerland. According to Meteo Switzerland, the peak was reached in Payerne (canton of Vaud). There the thermometer showed 36.5 degrees shortly before 4 p.m. It was similarly hot in Geneva (36.4 degrees) and Lausanne (36.3 degrees). 36 degrees were also registered in Basel and in Valais. The maximum values were somewhat more moderate with 33 to 35 degrees in the Mittelland and in Eastern Switzerland.
The temperatures remained a little lower than the meteorologists expected in advance. New record values for August have not been reached in the lowlands. These are 39.3 degrees in Geneva (measured on August 24, 2023) and 38.6 degrees in Basel (measured on August 13, 2003).
According to Eugen Müller, a meteorologist at Meteo Switzerland, this was the case that Sahara dust was shipped to the Alpine region with southwestern winds in 2000 to 4000 meters. The dust particles dampened the sunlight, which means that the actually existing heat potential of the air mass was not exhausted.
24 degrees at 1500 meters
How high this potential was can be seen when you look at another atmospheric floor. In the middle altitudes (around 1500 meters), the air -flowing air showed properties that very rarely occur in our latitudes.
View from Uetliberg to Lake Zurich: At this altitude, the heat wave made itself felt in a special way on Wednesday – the air was practically no longer cooling during the night.
Photo: Doris Fanconi
Meteo Switzerland starts a weather balloon with a radio probe twice a day from Payerne. This probe measures values such as temperature, moisture or wind direction and wind force at different altitudes. “The radio on the night of Wednesday showed a temperature of 24.2 degrees at a height of around 1500 meters,” says Eugen Müller. This is ever measured in August. The all-time record-25 degrees, measured on August 1, 1983-was barely not reached.
Experimental Map analyzes The meteorologist Markus Pfister suggests that the temperature in the above altitude in the outermost southwest of Switzerland and in Valais, where no radio on the risks are made, could even have risen over 25 degrees in some areas.
Heads Air from the SUBTROPRIPs
Whether a record or not: the air mass in Switzerland was brilliant on Wednesday. If you look at where she originated, it is not surprising. Using so -called reverse trajectors, meteorologists can trace the origin of the air on different height levels for over several days.
These trajectors show that the air that reached Switzerland at midnight on Wednesday came to us in adventurous paths. It flocked from the western Mediterranean to Western Sahara and the Atlantic via Portugal and Spain to the Alpine region.
The graphic shows the origin of the air masses at various height levels (from about 2000 to 5500 meters) on Wednesday (midnight) over Switzerland.
Those: Wetter3.de/gfs
This subtropical “broth” not only caused striking warmth in the lowlands, but above all at higher weather stations. In height, however, the temperature maximum was less exceptional during the day, but rather the temperature minimum at night. The thermometer on the Bantiger near Bern (1096 meters) sank not below 25 degrees until early Wednesday morning. The at night was also 25 degrees on the Zurich Uetlibergturm (1016 meters).
This is not atypical in this weather conditions. In contrast to the lowlands, where the air can cool down near the ground during the night, this effect does not come into play in the mountain areas. Even on the almost 1700 meter high La-Dole Jurag summit at Geneva, there was therefore a tropical night with low values of 21 degrees, and the temperature remained well above the freezing point on the Jungfraujoch (3580 meters).
The current heat wave will continue in the coming days, but it weakens. While the temperatures in western Switzerland are expected to be over 30 degrees by the middle of the next week, they will fall under the heat brand in German -speaking Switzerland from Saturday. In addition, the thunderstorm risk increases from day to day. At the latest on Saturday, thunderstorms must also be expected relatively widespread in the lowlands.
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