The summer's results are mixed.
But the summer period is not completely over, as shown by the very high temperatures, for the beginning of September, which affect France this week.
The values are well above normal in most of the country.
They reach remarkable levels in particular in the West and the South-West where it was Monday up to 10 ° C to 12 ° C above the average of the season.
In Brest (Finistère), it was over 30 ° C, which had only happened twice before since the start of the surveys, the first in 1961 and the second last year.
Elsewhere in Brittany, heat records have been broken, according to Météo France.
It was 31.1 ° C on the island of Groix, in Morbihan, and 30.5 ° C at Belle-Île, in the same department.
🌡️ Monthly records broken (provisional values at 5 p.m.) on other stations:
- Ile de Groix (#Morbihan, 41m, opened in 1921) with 31.1 ° C (previous record 31 ° C on 04/09/1929);
- Belle Ile (Morbihan, 34m, opened in 1930) with 30.5 ° C (previous record 29.9 ° C, on 09/05/2004).
- Météo-France (@meteofrance) September 6, 2021
Temperatures will continue to be very high on Tuesday and to break records.
Météociel does not exclude the possibility of reaching 40 ° C in certain areas of the South-West.
In history, such a level has only been reached twice in France in September.
For what is shaping up to be the hottest day of the week, here are some examples of maximum expected temperatures, according to The Weather Channel.
A few max T ° C today, the hottest day of the week:
37 ° C in Pau
36 ° C in Bordeaux
32 ° C in Bourges
31 ° C in Brest, Lyon, Orléans
30 ° C in Paris, Toulouse, Montélimar
28 ° C in Lille
27 ° C in Strasbourg and Nice
27 ° C in Marseille
We can locally exceed 38 ° C in the SW.
pic.twitter.com/8qD2lJkePB
- The Weather Channel (@lachainemeteo) September 7, 2021
These two maps allow us to compare some expected temperatures and the records still in force in the same places.
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In Paris, it will have been over 30 ° C for more days than the average for the years 1981-2010
The case of Paris is particularly remarkable.
As François Jobard, of Météo France, points out, the capital is preparing to experience four days in a row at more than 30 ° C between Sunday and Wednesday.
This has never happened since the reference meteorological station in the capital was moved to Parc Montsouris in 1948. With 12 days at over 30 ° C, the year 2021 would then include more than the average for the years. from the period 1981-2010.
If we observe 4 consecutive days> = 30 ° C in #Paris as planned (from Sunday to Wednesday), this will be unheard of in September since the change of shelter (May 1948) at Montsouris.
This would make a total of 12 days> = 30 ° C for 2021, (average 1981-2010: 11).
In 2018: 26 days.
pic.twitter.com/pzIqfVbpwx
- Francois Jobard (@Francois_Jobard) September 6, 2021
The other consequence of these temperatures is the nighttime heat.
In the west, the night from Monday to Tuesday is thus considered "tropical" since the temperature has not dropped below 20 ° C, as pointed out by Alexandre Flouttard, of Météo France.
Some minimum temperatures will be considered nighttime heat records if the temperature on Tuesday does not drop below overnight values by 8 p.m.
The time slot used to validate a record goes from 8 p.m. to 8 p.m. the next day.
"Tropical" night (Tº min> 20 ° C) from south Brittany to the south-west with 23 ° C at 7 am in #Toulouse where the heat was maintained because of the autan wind .., 28 ° on the Basque country (Soccoa) by fohn effect pic.twitter.com/FJRsKww2Z7
- Alexandre Flouttard (@ stormchaser_a81) September 7, 2021
In Paris, the temperature also remained high. The Météo France station, official and which therefore obeys precise rules such as not being located in the middle of buildings, remained above 20 ° C until between 2 hours and 3 hours. It took between 6 and 8 hours to get between 17 ° C and 18 ° C. A meteorological station of the so-called secondary network, located in the Latin Quarter, therefore in the middle of the dwellings and which corresponds more to what the inhabitants live, remained above 20 ° C. It still read almost 23 ° C at 2:30 a.m.
Thunderstorms will start to gradually lower temperatures.
The first will concern the West at the end of the day before gaining a wide swath from the north to the south of the country on Wednesday and continuing on Thursday.
These maps from The Weather Channel allow you to visualize the expected temperatures and the progress of thunderstorms until Thursday.
The wave of #heat will mainly concern the west of France in the coming days.
Here are the #temperatures we can expect 🌡️ They will drop moderately on Thursday, after the #storms have passed.
pic.twitter.com/tNl1Qswjdl
- The Weather Channel (@lachainemeteo) September 6, 2021
After the #heat, it will be necessary to watch the #thunderstorms, the first of which will erupt tomorrow evening in central-western France.
They will slowly cross the country eastward from Wednesday to Friday.
They will be violent, with abundant rains in Languedoc-Roussillon.
pic.twitter.com/CVZXMaiAjL
- The Weather Channel (@lachainemeteo) September 6, 2021
Météo France has already issued a warning about these thunderstorms.
“After the strong heat of Monday and Tuesday, remarkable for the beginning of September, the situation will deteriorate markedly on Wednesday.
Indeed, an active storm front will sweep the regions of the west of the country.
These thunderstorms will be accompanied by intense rains, sometimes hail and strong squalls.
In the Languedoc, during the night from Wednesday to Thursday, an episode of very heavy precipitation is expected.
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