The heat episode should be concluded on Sunday with thunderstorms on most of France, accompanied by strong localized precipitation.
Le Monde with AFP
Scorching temperatures continue on Friday August 12, the peak day of this third heat wave. Nineteen departments of the Atlantic and South West facade are on orange heat wave, while Corsica is on orange vigilance for violent thunderstorms on the night of Friday to Saturday. The heat episode should end Sunday with thunderstorms on most of France, accompanied by strong localized precipitation. However, they will be insufficient to remedy the historic drought, according to the forecasts of Météo-France.
Maximum temperatures “are upwards in several regions”, according to Météo-France . The city of Toulouse recorded 40 degrees at 4 p.m. The temperature reached 36 and 34 degrees in Bordeaux and Paris. Temperatures will remain high in the night, often with 18 to 21 degrees on the Atlantic facade and the South West, 21 to 24 degrees around the Mediterranean.
From the night from Friday to Saturday, “an active pluvio-stormy pass will sweep the coasts of Corsica”, “with strong precipitation, hail and gusts of wind”, underlines Météo-France. They will quickly dissipate in the morning to make room for a drier weather. On the Mediterranean coasts, the day will start under an alternating clouds and clarified, the latter winning it on the French Riviera.
On the Atlantic side, the sky will be rather gray in the early morning on the coast. Clouds will gain ground in the afternoon. A stormy degradation will then be set up on the Pyrenees before spreading in the evening to the plains of Occitanie and New Aquitaine.
The clouds will then win the Pays de la Loire and Brittany, where some thunderstorms will also be possible. On the rest of the regions of the northern and further east, a sunny time will remain dominant.
“Risk of fairly large runs”
Thunderstorms, which will go back from the southwest from Saturday evening, are expected to be the strongest around the Massif Central and the Rhône valley, “and can give in places accumulation of precipitation up to 30 to 50 MM “, Météo-France note.
The strong cumulative “will fall on very dry soils, with risks of fairly large streams” which will not allow to absorb water and increase the risk of floods “and the risks of hailstones”, In clear custody Chanal, forecastist, during a press briefing Friday evening.
Furthermore, “thunderstorms give accumulation of very heterogeneous and localized precipitation, insufficient to compensate for a” drought that affects the whole territory “, she added.
“Dryness has lasted for a long time, plants are suffering, and it will take small regular rains to hope that this vegetation leaves,” said Romaric Cinotti, referent Fires of Météo-France vegetation. “The absence of vegetation is an aggravating factor for runoff, because the vegetation participates in retaining water,” he also noted.
The impact of thunderstorms on current fires, especially in Hostens in Gironde, remains difficult to predict: “They can have an opposite effect, causing strong gusts and winds of wind which can worsen the danger [and are] very problematic for firefighters. “Besides,” the impact of lightning is the first natural cause of fire, “recalled Romaric Cinotti, lightning that can fall away from the storm cell, in a little area watered.