[Updated July 11, 2023 at 3:22 p.m.] The first thunderstorms broke out in central France. An episode of heat wave is currently mixed with a wave of thunderstorms which could be of exceptional intensity this Tuesday, July 11, 2023. All this will be locally accompanied by gusts of wind which can reach 150 km / h and hailstones of several centimeters in height. diameter according to Météo France.
The national meteorological service has updated its national vigilance bulletin. Eclairs lovers will be able to feast since 22 departments are thus on orange storm vigilance for this day of July 11. Gusts of wind at 150km/h, hailstorms and violent thunderstorms: this is the expected program in north-eastern and central-eastern France. Keraunos, the French observatory for thunderstorms and tornadoes, has thus activated its maximum level of alert, something unheard of since June 2014. This level five alert has only been used five times since 2005. After a brief period high heat, the weather will deteriorate with the passage of storm cells. The electrical activity should be intense according to the forecasts of the observatory.
Storms that can be extremely violent are expected in the northeast with a significant risk (estimated at 25%) of gusts > 150 km/h when passing supercells or arched systems. Violent hailstorms are expected in isolation: https://t.co/dookCX0aeA pic.twitter.com/GZFnr0GG2f
— Keraunos (@KeraunosObs) July 11, 2023
A first stormy depression should fly over these territories this afternoon. The first flashes are expected in Auvergne then they should move towards Alsace. Météo France is thus expecting very strong gusts of wind that can reach 100 to 130 km/h, very locally a little more, heavy hailstorms, with a risk of large hailstones several centimeters in diameter and 20 to 40 mm of rain in less than 30 minutes or 1 hour.
Which departments are on thunderstorm vigilance?
The departments warned by Kéraunos, namely Moselle, Bas-Rhin, Meurthe-et-Moselle, Vosges, Haut-Rhin, Territoire de Belfort, Haute-Marne, Haute-Saône, Doubs, Jura, Côte-d’Or, Saône-et-Loire, Ain, Rhône, Allier , Loire, Puy-de-Dôme, Haute-Savoie, Cantal, Haute-Loire, Aveyron and Lozère have also been placed on thunderstorm orange alert by Météo France, with most also under heatwave alert .
According to Kéraunos forecasts, a risk of tornado formation exists, with a 5 to 15% chance of this happening. Regarding hailstones of at least five centimeters in diameter, the observatory estimates the occurrence of this phenomenon to be between 15 and 30%. During the Pentecost weekend in 2014, the last time Keraunos activated its maximum level of alert, the hailstorms had been remarkable with pieces of ice 8 cm in diameter in the Paris region and even 12 cm in Loiret!
