The aptly named “Lucifer” anticyclone.
It is so hot in southern Italy that experts and the media have dubbed the meteorological phenomenon that hovers over the peninsula with the nickname Satan.
In the center and south of the country, temperatures exceed 40 degrees and a record of 48.8 degrees was recorded in Sicily on Wednesday.
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If the national meteorology confirms these data, it will be the highest temperature ever recorded in the territory of our transalpine neighbor.
The phenomenon is not unique to Italy: it is observed throughout the Mediterranean basin, from Tunisia to Spain, and begins to rise towards France.
We take stock.
What is happening in the Mediterranean basin?
The region has been facing a heat wave for several days. "Europe on the eastern Mediterranean side experienced exceptionally warm conditions during the first ten days of August", indicates Météo France. Greece and Turkey paid the price: “Temperatures were able to reach or even exceed 40 degrees, with monthly records broken at the beginning of August in Greece. The two countries, faced with very dry climates, have suffered fires of rare violence. Three people died in Greece, eight in Turkey.
The very hot air masses then migrated towards the central and western Mediterranean this week, "in the direction of Italy, the Maghreb and Spain", notes Météo France.
Monday and Tuesday were historic days in Tunisia.
The capital, Tunis, broke its absolute heat record on August 10 (48.9 ° C, against 47.4 ° C in 1983).
The day before, the country had broken its national heat record for August with 49 ° C.
Neighboring Algeria is not spared either.
According to the latest report, 69 people died in fires intensified by the extreme heat in Kabylia, in the North.
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In Italy, the temperature reached 47 ° C in Sicily (Lentini) on Tuesday.
Four people have died in half a thousand fires ravaging the country.
Spain and Portugal have also entered a heat wave with very high risk of fires in much of the peninsula, authorities in both countries warned on Thursday.
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- VigiMeteoFrance (@VigiMeteoFrance) August 12, 2021
The phenomenon is gradually gaining in France, but the country should not be subjected to the heart of these scorching air masses.
"Very hot weather concerns the south-east of the country and the Rhone valley", indicates Météo France, which placed five departments this Thursday afternoon - the Var, the Alpes-Maritimes, the Alpes-de-Haute-Provence , Drôme and Ardèche- in vigilance orange heat wave.
In these departments, temperatures will often be between 36 and 39 degrees, even exceeding 40 degrees in Provence.
What role does the “Lucifer” high pressure play?
The Mediterranean basin is currently under a dome of heat.
In scientific language, we speak of a blocking atmospheric circulation: high pressures trap hot air in a region.
This heat bubble is directly linked to the presence of the very powerful “Lucifer” high pressure system, which blocks any intrusion.
"The hot air settles in and can no longer be evacuated because there is no disturbance," explains Parisian Pascal Scaviner, head of the forecast service at the Weather Channel.
"This mass of very hot air has rare characteristics, even for the countries bordering the Mediterranean, with 10 to 15 degrees at around 3000 m and 25 to 30 degrees at an altitude of 1500 m", specifies Météo France on its website.
What are the forecasts?
In Italy, it is especially the center and the north of the country which will undergo this episode of strong heat, because "the temperature anomalies will be 4 to 8 degrees above the normal for the season", explains Pascal Scaviner.
In Rome, temperatures are expected to be around 39 ° C, compared to 32 ° C in August usually.
“The feeling will be all the stronger as this region is continental, unlike Sicily where a phenomenon of breeze can attenuate the impression of heat.
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In Spain, "the mercury will probably and locally rise to 45 to 48 ° C on Friday and Saturday, records are clearly threatened since the absolute Spanish heat record is 47.4 ° C", specifies Météo France.
In France, the hot weather will persist until Sunday, in particular in the Mediterranean regions and the Rhône valley.
We will have to wait until the end of the week for another, more powerful anticyclone to push back “Lucifer”.
"This second high pressure will increase in the North Atlantic and shift the disturbances circulating in the British Isles towards Central Europe," says Pascal Scaviner.
In the north of France, the weather “will change dramatically”.
“We will lose 8 degrees in 24 hours in Paris between Sunday and Monday,” cites the meteorologist as an example.
This supply of fresh air "will gradually descend towards the south, as far as Italy".
On the other hand, the “Lucifer” anticyclone will remain “from North Africa to the Balkans”, continues Pascal Scaviner.
Is this usual?
If the heatwave observed in France is not "remarkable for a summer period", the phenomenon encountered in the Mediterranean basin is "exceptional", notes Météo France.
And Pascal Scaviner underlines: “With global warming, it will be more and more frequent.
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The region is indeed one of the areas where the effects of climate change are felt the most, according to a report from the Union for the Mediterranean released in 2019. “We will have more climate variability, with changes in the weather. quite radical.
However, it is this variability that contributes to creating heat domes, ”explains the meteorologist from the Weather Channel.