Weather vigilance in Brittany departments for strong electrical activity

After the sun, thunderstorms. Beginning May 2025thunderstorms are expected in Brittany. Departments are placed in yellow vigilance by Météo France.

Several departments in yellow vigilance

Morbihan is placed in a state of yellow level (level 2/4) forR Risk of thunderstorms on Thursday 1ᵉʳ May 2025 from 8 p.m. until midnight. This is also the case with theIle-et-Vilaine, Côtes-d’Armor and Loire-Atlantique.

Vigilance is for the same times for the other three departments.

An expected stormy salvo

“At the end of the afternoon of Friday May 2, 2025, following evening and night, showers and thunderstorms arrive through the Atlantic facade and gradually cross the region,” said Météo Brittany.

“A stormy degradation is expected at this weekend,” confirms Breton weather which indicates that it will happen in two stages:

• A first thunderstorm mobile storm in the night from Friday to Saturday by the Atlantic facade.
• A thunderstorms at midday on Saturday

According to Breton weathera “cold drop wins the Gulf of Gascogne” and “brings cold air at altitude while temperatures sometimes climb above 25 ° C this Friday in Brittany.

Littloral of Morbihan and Finistère for the first sequence

“Thunderstorms broke out in the early afternoon on the Asturias (north-west of Spain). They cross the Gulf of Gascogne to reach Brittany in the night from Friday to Saturday. These thunderstorms move fairly quickly. However, they are accompanied by a sometimes strong electrical activity on the Morbihan coast and southern Finistère. By progressing in the land, they destroy themselves and the temporary agitation are fading, ”predicts Breton time.

Other sectors for the second sequence

“The flow is much less mobile on Saturday during the day since a conflict of air masses operates between hot air in the south and east of France and the much fresher air which wins the North Sea,” said Breton weather.

Brittany is on the trajectory of this conflict, in particular the north of the region. Thunderstorms are bursting in the afternoon. They are not very mobile and generate sometimes important rainfall cumulative. The stormy risk exists on the entire area colored in pink on the map but a most significant signal is identified on the Trégor, the Leon, the Arrée, the Argoat and the Kreiz Breizh. Cumulation over 30 mm in the space of an hour can be measured.

“In the evening, the stormy risk spreads south But it becomes much more marginal. The situation is monitored, in particular the possibility of sometimes very rainy cells on Saturday afternoon, ”said Breton Time.

Sources: Breton weather, Brittany and Météo France weather

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