The thermometer is again in danger of panicking. Since Sunday September 11, the heat has returned to part of mainland France. A heat peak arrived from the southwest due to a small depression located off the Iberian Peninsula. Franceinfo has three questions about the weather forecast for the next few days.
1What to expect for the next few days?
Temperatures could approach record levels for the season on Monday afternoon in southwestern France. Mercury could graze monday “36, 37 or 38 ° C in certain areas, in Gironde or in the Landes”, details at franceinfo Florian Hortala, forecaster at Météo France. Outside the South-West, temperatures should rather be between 30 and 35°C in a second zone extending to the edge of Brittany, then between 25 and 30 °C over the rest of the country and even slightly below in the northeast.
strong peak #heat :
Remarkably high temperatures for a second decade of September from this Sunday, and especially tomorrow #Monday on the #South West.⚠️⛈ Short-term heat.
Stormy deterioration from Tuesday, particularly in the south of the country. pic.twitter.com/19kkEfcOyG— Meteo-France (@meteofrance) September 11, 2022
The heat wave should dissipate quickly, but then stagnate over the Mediterranean with “disastrous consequences on ecosystems”remember on Twitter climatologist Christophe Cassou. In the lands, “we will have a stormy deterioration for Tuesday with a slight instability, and above all a deterioration on Wednesday with a high risk of thunderstorms around the Mediterranean”, continues Florian Hortala. Another stormy degradation should extend from Brittany to Alsace, passing through the Paris Basin.
As the week progresses, temperatures are expected to approach seasonal norms. “Temperatures should drop from Wednesday-Thursday in the North and from next weekend in the Southdetails Florian Hortala. In the North, we have a drop in temperatures over the weekend with on average 8°C for the morning and 19 for the afternoon.”
2What will be the consequences for precipitation?
Difficult to be precise several days before stormy phenomena, but “the atmospheric circulation will be very favorable to very strong precipitation events”, says climatologist Christophe Cassou. Météo France has also issued a warning on the home page of its site to prevent “intense rains and sometimes violent thunderstorms this week”.
“The rains that we will find around the Mediterranean are the result of a fairly typical phenomenon. On this type of episode, we have very intense rains and in very large quantities in a few hours”details Florian Hortala. The forecaster warns several departments that should be particularly affected, such as Hérault, Gard, Ardèche, Bouches-du-Rhône or Vaucluse.
3How can these phenomena be explained?
Regarding the heat peak, it is a “pretty typical situation, with an air depression blocking the west of the country off the French and Spanish coasts, and this brings a flow of warm air from the south”Explain Florian Hortala. This small depression also corresponds to the former tropical storm Danielle, which has just crossed the Atlantic.
The peculiarity of this #HeatFeather comes from its link with the tropical dynamics because the small depression off the Iberian Peninsula which generates it corresponds to the ex-cyclone#Danielle who made his tropic-extratropic transition https://t.co/3yykRfGdb8
9/N— Christophe Cassou (@cassouman40) September 10, 2022
Are this expected heat peak and its consequences new evidence of climate change? “HASBefore the 2000s, this would not have given such high temperatures, the context of warming allows us to have records. meet with these masses of hot air which give temperatures of 36, 37 or 38 ° C, it is not normal”replies Florian Hortala.
The severe weather that is likely to affect France again this week also has an indirect link with global overheating. “A warmer climate increases moisture transport in weather systems (our pumps), which intensifies wet eventsexplains researcher Christophe Cassou on Twitter. The increase in the atmosphere’s capacity to hold moisture (+7% per degree) results in a similar intensification for extreme rainfall events (…), increasing the severity of flood risk.”