Many temperature records have fallen or will be. If these strong heat do not prejudge the occurrence of heat waves during the summer, they aggravate the current drought.
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Hot kick on France. With 33 ° C in Toulouse, nearly 30 ° C in Paris or 27 ° C in Lille, Wednesday, May 18, the country undergoes an episode of hot weather qualified by Météo France as an exceptionally early, durable and intense “. Many records have already fallen or will be, so that May should most likely be the warmest ever recorded in France, dethroning May 2011.
The strong heat threshold – From 30 ° C – was reached on a third of the weather network France on Wednesday . Temperatures are currently 10 ° C higher than seasonal normal (1981-2010) for the Pyrenees region to Lyonnais, and between 5 to 8 ° C in the North West. The only spared regions are those close to the Mediterranean coast, between Toulon and Nice, and the Channel.
Mercury will climb again in the coming days to flirt with 35 ° C in many localities. “Some cities may experience at least five days in a row exceeding 30 ° C, a extremely rare event in May,” said Olivier Proust, forecaster at Météo France. This phenomenon should, for example, be extended for seven days in Lyon.
Wednesday also marked the thirty-eighth day in a row with higher temperatures than seasonal normal. “Started on April 11, this series should continue at least until May 24, a minimum of forty four days, dethroning, for spring, the 2007 record which was thirty-eight days,” warns Gaétan Heymes, forecastist at Météo France.
The hot weather is expected to continue until Friday in the northwest of France, and until this weekend in the south, after a respite on Thursday and Friday. Temperatures should then fall down Monday 23 and Tuesday 24 May. If these strong heat do not prejudge the occurrence of heat waves during the summer, they aggravate the current drought.
“This phenomenon is called upon to reproduce”
Despite its unprecedented character, this episode does not correspond to the definition of a heat wave. For this categorization, “the national thermal indicator”, average temperature of temperatures noted in thirty points spread across the mainland, must exceed 25.3 ° C for three consecutive days. “We are rather at 21 ° C or 22 ° C, which is very hot for the season, but the temperature descends at night”, specifies Olivier Proust.
In question in the current phenomenon: an anticyclonic ridge, that is to say an axis of high pressure, which extends from the Maghreb to the banks of the Baltic and allows the rise in very hot air. It is not a heat dome, as was the case in Canada in June 2021, since the air was circulating. “With climate change, it is no longer enough to have an extremely rare atmospheric circulation to know such episodes. More conventional circulation is enough to produce exceptional temperatures since it carries masses of air rendered warmer by warming, Note Olivier Proust. This phenomenon is called upon to reproduce, which is very worrying. “
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