A rainy week ahead for France

Wednesday 25 September marks the start of a period of heavy rain that will last for the whole country. An atmospheric river, associated with a low-pressure system called Aitor, will bring disturbed weather, with sustained showers until Friday.

Origin of the precipitation

This atmospheric river is the result of a meeting between polar air from the North Atlantic, heading towards the British Isles, and a south-westerly flow of mild air over southern Europe, according to Météo-France.

From the morning, the first rains will appear from the west, with a rapid deterioration in weather conditions in Brittany, followed by the Pays de la Loire and Normandy, where significant showers are expected. At the same time, strong gusts of wind, reaching up to 90 km/h, will accompany this bad weather.

In the south-west, the skies will remain partly overcast but dry, while the south-east will enjoy sunny weather. Morning temperatures will vary, with 9°C in Grenoble, 13°C in Paris, Marseille and Nantes, and 16°C in Bastia.

More precipitation

As the afternoon progresses, the rain will spread over a vast north-western quarter, including the whole of the Île-de-France region. Météo-France specifies that the cloud cover will affect almost all the regions, except Provence-Alpes-Côte d’Azur, while the rainy disturbance will progress towards Poitou-Charentes, the Centre, the Paris basin and Hauts-de-France.

Temperatures will remain in line with the season: 16°C in Rouen, 18°C in Paris, 23°C in Bordeaux, 24°C in Marseille and Toulouse, and up to 28°C in Perpignan.

A slight lull before the rain returns

On Thursday, clear skies are expected to appear in Brittany and Normandy, but the other regions, with the exception of a small part of the south, will continue to experience often heavy rain. Temperatures will drop slightly, with lows fluctuating between 10 and 14 degrees inland, and highs of 17 to 18 degrees along the Channel coast, while the shores of the Mediterranean could reach 22 to 26 degrees.

The situation is unlikely to improve much on Friday, when showers will persist over much of the country. Sustained rain will give way to showers over most of the country, but Haute-Normandie and the north of Hauts-de-France could see worrying accumulations of rain over the next three days.

We’ll have to wait until Sunday for a break in the bad weather, but further rain is expected from Monday over the north-western quarter, with almost the whole of France affected from Tuesday.