“Whirlpool phenomena, waterspouts or even tornadoes could also occur,” warns Météo-France.
Eight departments of the Mediterranean arc are placed in orange vigilance on Tuesday due to the risk of potentially violent storms, which can lead to “hail falls and heavy accumulations of precipitation”, announced Météo-France. The departments concerned are: Aude, Tarn, Aveyron, Hérault, Gard, Vaucluse, Bouches-du-Rhône and Var.
On an arc from Aude to Var, the storms that started Tuesday afternoon will move from east to west during the night. Without formally using the term, Météo-France indicates that the situation approaches the definition of a Mediterranean episode, which corresponds to violent storms most often caused in autumn by upwellings of hot, humid and unstable air from of the Mediterranean.
In Aude and Aveyron, which will be hit first, “local accumulations of 20 to 50 mm are expected in less than an hour” and “gusts of winds around 70 to 90 km / h may occur “, before fading into the night.
In Hérault and Gard, the forecast rainfall could reach 80 mm “in a very short time”, or even “100 to 130 mm” if the storms become stationary, a particularly risky situation but difficult to locate in advance.
“Whirlpool phenomena, waterspouts or even tornadoes could also occur,” warns Météo-France. “In the second part of the night, these violent storms will shift towards the lower Rhône valley then reach the Var” Wednesday morning. On Wednesday, “after a few hours of calm, a new, very stormy episode will take place from Languedoc to Provence”.
“In a more isolated way, the other departments of the south-west, placed in yellow vigilance on Tuesday, may experience strong thunderstorms with hail,” warned forecaster Frédéric Nathan, during a press briefing from the meteorological service. .
In addition to the storm threat, the Hérault and the Gard have been placed on yellow alert for the risk of flooding.