From Wednesday, the whole country will be affected by a heat wave which could intensify further.
Those who have laid down their towel on the French coast will surely rejoice. But the others are likely to pale at the sight of the weather forecasts for the next few days. If uncertainties still hover over the evolution of the situation from the weekend, France is indeed facing a new heat wave which should spare no territory.
As of Monday, a rise in temperatures has been observed in France, but it is the South-West which should show very high temperatures first, with “in Aquitaine and southern Brittany, an average temperature of 34°C, maximums up to 39°C and night temperatures that will not fall below 20-21°C”, warns Pascal Scaviner, forecaster for La Chaîne Météo (a company of the Figaro group). On Wednesday, the whole country should be affected by temperatures much higher than normal for the season, with the hottest zone which will extend from the South-West to the Center-West and will reach the Paris Basin.
Southern European countries are all affected, with higher temperatures in Spain
Pascal Scaviner, forecaster for La Chaîne Météo
This situation is mainly due to a heat dome which has set up over Morocco and is rising to the west towards France. “This dome acts as a lid that traps hot air. Gradually, it compresses, and this compression physically causes an increase in temperature., explains Sébastien Léas, forecaster at Météo France. This dome does not only affect France. “The countries of southern Europe are all concerned, with higher temperatures in Spain, but temperatures which could remain high for longer in Italy”explains Pascal Scaviner.
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If meteorologists agree on a slight decrease in temperatures Thursday and Friday north of the Loire, the evolution of the situation over the weekend remains very uncertain for the time being.
Worsening of the situation from this weekend
It is a “cold drop” currently located above the Azores which could cause the situation to worsen this weekend, with a rise in temperatures and reaching a peak on Monday July 18. This phenomenon of “cold drop” is due to a mass of cold air blocked in altitude, at approximately 5000 meters. “This cold drop generates a circulation of hot air masses around it. The “feathers” or “heat plumes”, which we talked about during the heat wave last June, are born in front of these “cold drops”», explains Sébastien Léas. But the different possible models according to the data currently available do not agree. “We cannot yet determine if this “cold drop” will come up from the Azores, if so at what speed, or if it will push back the heat dome or not”warns Pascal Scaviner.
If in the most pessimistic scenario the 40°C mark could be passed at the beginning of next week in several regions, the most optimistic scenarios still predict high temperatures, in particular over the entire south of the country where the hot air will stagnate. “We may not reach the records that were set last June, but it is possible that this episode of high and very high temperatures will last longer than the previous heat wave”notes Pascal Scaviner.
While the heat wave that hit France in June was followed by sometimes intense thunderstorms, this time no stormy episode is expected in the days to come. The drought, already very marked in many departments, is therefore likely to worsen. If storms would not be enough to fill the water tables, they would at least participate in cooling the atmosphere and moistening the ground on the surface.
This heat wave is the 44e since the beginning of the census by Météo-France, in 1947. Global warming will make these events “more frequent, earlier and later, resulting in a longer and hotter summer period”warn the experts of Météo-France.