"Atmospheric river" Severe weather phenomenon could hit Switzerland
The next few days will be particularly turbulent in terms of weather: several cold fronts and a warm front will collide and cause turbulence. In addition to heavy precipitation, strong winds are expected.
Before rain covers the whole country on Thursday, Switzerland should enjoy the prospect of sunshine again on Wednesday, as long as it can still be seen between the clouds. Temperatures will rise, especially at high altitudes - with a zero degree limit above 3000 meters.
On Thursday night, a rain front will sweep across the country, bringing heavy rainfall and strong winds. The Föhn wind intensifies in the Alps. The day is characterized by persistent rainfall.
At high altitudes, there will only be snow above 3000 to 3500 meters. The south-westerly winds intensify into a storm that reaches its peak during the night from Thursday to Friday.
"Atmospheric river" phenomenon
Wind gusts of between 60 and 90 km/h are expected between Wednesday evening and Friday morning on the Central Plateau, in the Lake Geneva basin, in the Jura and in the Ajoie - with peak values of over 100 km/h on the Jura ridges and in the Alps.
The precipitation will be particularly heavy on Thursday afternoon and evening, amounting to between 40 and 90 mm depending on the region. According to Meteo Robin, the Chablais will be one of the areas most affected by the storm.
A phenomenon of the "atmospheric river" type could intensify the rainfall locally - with torrential rainfall in some regions. This could lead to heavy runoff and potentially to flooding.
What is an atmospheric river?
- Atmospheric rivers (AR) are very moist air currents.
- They can have a vertical extent of up to three kilometers and be up to 2000 kilometers long.
- When they encounter obstacles such as the Alps, the Rocky Mountains or the Pyrenees, they lead to heavy precipitation.
- This phenomenon was recognized in 1998 by scientists at MIT through the analysis of European weather data.
Last rains before Indian summer
On Friday, there will be a mix of clouds, sunshine and scattered showers before a new cold front arrives on Saturday, bringing with it more showers and falling temperatures.
From Sunday, an area of high pressure will establish itself, offering ideal conditions for an Indian summer. This high-pressure system will channel dry air into Central Europe, guaranteeing sunny and friendly weather for Sunday, Monday and Tuesday.
This Indian summer phenomenon is a recurring phenomenon in our region and occurs about five out of six years.