How can storms, phenomena as rumbling as they are dazzling, so often go under the radar of meteorologists? Since the end of May, storm alerts have followed heatwave alerts without always much precision, as the phenomenon proves difficult to predict. Fueled by the heat that has accumulated in the days preceding them, stormy episodes are often expected “in the coming days”, announcing a cooling of the atmosphere that is difficult to date precisely.
Despite a certain imprecision and in order to prepare for any eventuality, Météo France has placed twenty-one departments in the Center-East on orange alert for thunderstorms this Thursday, July 16. Thunderstorms may be accompanied by gusts of wind likely to occasionally reach 120 km/h, intense electrical activity, dense rain or even hail, sometimes of large diameters, warns Météo France in its latest bulletin. Vigilance could be extended to other departments depending on changes in weather conditions. Because when it comes to storms, everything can change very quickly.
Atmospheric cocktail complex
A true atmospheric cocktail, a storm is a highly complex phenomenon. Its formation depends on the air temperature at the surface and at altitude, on the variation of the wind depending on the altitude and the humidity of the air, but also “on the very variable local conditions of temperature and humidity of the soils, influenced by the nature of the soils, the type of vegetation as well as the configuration of the relief”, explains Météo France. It is these multiple variables that cause storms to affect very limited geographic areas, only a few kilometers, and evolve over a short period of time – from a few tens of minutes to a few hours.
🟠 Extension of orange thunderstorm vigilance for the departments of Creuse, Yonne, Aube, Haute-Marne, Vosges, Bas-Rhin for the start of the event at 4 p.m. this Thursday.https://t.co/SBcDaJ3wuk https://t.co/sFgDhzzRi4
— Météo-France (@meteofrance) July 16, 2026
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Also, numerical models remain imprecise, because they only partially represent small-scale phenomena. Although we cannot guarantee that a storm will occur or not in a restricted area, these models nevertheless make it possible to identify “the geographical areas which provide favorable conditions for the development of cumulonimbus clouds”, specifies Météo France, and therefore for the triggering of storms. The most recent high-resolution models make it possible to gain in precision, and to more realistically simulate the evolution of the disturbance and the area concerned of the order of a few tens of kilometers. They do not, however, make it possible to determine their exact intensity.
An intensity which can sometimes cause heavy damage. This Thursday, July 16 in the morning, nearly 1,900 homes were still without electricity in Cher and Indre-et-Loire, after a storm transformed the streets into torrents and caused several trees to lie down. The day before, hailstones the size of tennis balls fell on part of France during a first stormy episode, particularly in the south of Ardèche, in Aubenas.
By lowering atmospheric pressure, the storms of this Thursday, July 16 should, however, have the merit of initiating a drop in temperatures. A breath of fresh air to get out of this third heatwave in a few weeks.
