While September started off hot, temperatures have dropped significantly in the middle of the week. Temperatures will rise a few degrees this Saturday before dropping again. In the middle of next week, it will be very cool for the season with the first snow at medium altitudes in the mountains.
For the past few days, the weather has been particularly unstable in France. Western Europe is located between two powerful anticyclones, one over the nearby Atlantic and the other over Russia. The very hot air that still affected us at the very beginning of the month (33°C in Lille on September 1st and up to 35°C in the Var) has evacuated and we have found temperatures close to or even slightly below seasonal norms in certain regions.
New contrast of west-east air masses this weekend
France is once again this weekend at the heart of a conflict of air masses between warm air rising from the Mediterranean and cooler air arriving via the Channel and the Bay of Biscay. A heat peak concerns the eastern regions on Saturday with temperatures approaching the 30°C mark in cities such as Nancy, Strasbourg and Lyon this Saturday while temperatures are struggling to exceed the 20°C mark along the Atlantic.
This situation of conflict between air masses is conducive to storms which will circulate this Saturday from the southwest towards the Paris Basin and the central regions.
Fresh air coming: autumn is setting in a little early
After the unstable and stormy weather of the weekend, we will find barely seasonal temperatures at the beginning of next week. With a flow that will turn northwest from next Wednesday, even cooler air from the north of the Atlantic will sweep over France.
Temperatures will fall well below seasonal norms next Wednesday and Friday. An active cold front could sweep across France from the northwest towards the Mediterranean with sustained rain, snow at medium altitudes on our mountains. Behind the front, the weather should remain unstable with showers in the plains and sleet in the mountains. Snow could whiten the ground from 1800 m, which happens early, but is nothing exceptional for a month of September.
This cool spell should not last with a trend towards warmer weather for the second half of September as our trend for the next 4 weeks predicts.
- La Chaîne Météo
Related News :