A week of May 1, looking for summer in the northern half of the country – Liberation

Bermuda Put on, sandals like Birkenstock At the feet and sunglasses on the nose. As of this Sunday evening and throughout the week of the May 1 bridge this Sunday evening, this summer panoply is likely to be drawn a bit in advance. For this « episode of early warmth », Météo France analysts provide temperatures worthy of a late May or early June.

This summer -looking weather is not a first this year. High temperatures have already been noted compared to normal a little earlier during spring.

This episode of heat from the North will be particularly remarkable at the level of the Channel and Brittany coasts. The forecasters count on a difference of 10 ° C compared to normal in this area. This increase in temperatures is explained by the influence of an anticyclone which extends between England, the North Sea and Germany. It is these high atmospheric pressures that allow the air mass of warm up slowly Over the week, more than a hot air intake.

Between Tuesday and Friday, the 25 ° C will be largely affected, especially in the northern half according to Météo France. For the day of Wednesday April 30, it is in Reims that it will make the hottest in France, with temperatures reaching 27 ° C. Conversely, the city of Toulouse should be the most « cold », with 23 ° C. Throughout the country, the expected values ​​will exceed normal more than 4 degrees.

According to meteorologist Guillaume Séchet, the peak should be reached on Thursday or Friday, and we could come close to or perhaps break heat records, writes the specialist on his X account.

Météo France services remind you, these high temperatures are not unprecedented for the period. In 2005, between April 28 and May 2, the weather organization noted, on May 1, 28.7 ° C in Paris, 29.8 ° C in Strasbourg, 30 ° C in Dax (Landes) and even up to 30.3 ° C in Vichy (Allier).

Upward temperatures do not necessarily laugh with good weather. At the start of the week, the sky blue will be hard to perceive, especially in the Eastern regions. Despite high pressures and climbing mercury, cold air at altitude may generate a hint of instability. Showers, even thunderstorms, could point and disturb this episode of heat.

Despite the impression that the seasons are less marked and more fluctuating than in the past – the fault in global warming -, it is advisable to be precise with certain terms: out of the question of speaking of « heat wave », only of an « heat episode ».

In France, a heat wave meets precise criteria since the creation in 1947 of the national thermal indicator. To enter this category, the indicator must exceed 25.3 ° C for at least three consecutive days, which is not the case for next week.

The heat wave ends when the indicator descends under 23.4 ° C for two consecutive days or when it descends under 22.4 ° C, even a single day. Météo France has identified 46 waves of heat in France since 1947, including 17 before 2000 then 29 after. The most recent of July-August 2022.