Weather alert: The heat wave shifts to the east before thunderstorms – The Weather Channel

By Regis CREPET, meteorologist
Posted 07/19/22, updated 07/19/22 11:48

Complete weather forecasts live by telephone on 3201* From Tuesday July 19 at 12:00 p.m. to Wednesday July 20 at 6:00 p.m. Situation The heat wave is shifting over the northeastern two-thirds of France and the Paris basin, where this Tuesday will be the hottest day of the episode. The 40°C mark can be reached there as far as Hauts-de-France, and down to the center-east and the Rhône valley. To the west, after a tropical night, temperatures rise much less during the day and the heat wave ends, with 10° to 15° C less than on Monday. This heat wave is linked to the rise of a depression off the coast of Brittany, which brings up hot air in a flow from the south. With the circulation of this depression towards the English Channel, the wind turns to the west on the Atlantic arc, explaining the drop in temperatures. The arrival of this cooler air now triggers thunderstorms, some of which were already breaking out at daybreak over Finistère. But it is late in the evening that we expect a marked stormy deterioration in the interior of Aquitaine and in the Midi-Pyrénées region. This partial degradation may be marked between 9 p.m. and midnight, to then fade as it moves up towards the central regions. The showers could locally be sustained with a risk of hail, but the watering will remain too localized and too short to improve the drought situation. These storms will rise during the night towards the Paris basin, then, Wednesday morning, to the northeast, being diffuse and of low to moderate intensity. This special press release may therefore evolve accordingly. Observation At the end of the morning, the hottest regions of France are Ile-de-France, Normandy, Burgundy and Hauts-de-France with temperatures already above 30°C at 11 am. We already recorded 32° in Lille, 33° in Auxerre, and 34° in Évreux, Caen, Paris and Saint-Dizier, as in Provence. On the other hand, under the foggy greyness, the south-west stagnated around 22° to 25°, with already 30° in Albi in the Tarn: but in these regions (Midi-Pyrénées and Occitanie), temperatures will reach 35° to 37 ° this afternoon when the sun will break through. This Tuesday morning:
At 9 a.m., temperatures were rising sharply and already sometimes above 25°C in regions ranging from the Paris basin to Hauts-de-France, with:
26° in Rouen
27° in Paris
28° in Caen and Lyon
In the southwest, the temperatures were only 20° to 23°, and 24° in Toulouse, under a gray and misty sky.
Meanwhile, thunderstorms were breaking out over Finistère. The night was tropical with temperatures not dropping below 20° to 24°C over the western half of France and in the southeast.
Thus, at daybreak, exceptional values ​​of:
30°C in Dourgne (81)
29.7°C in Longueville (50)
28° in Plerguer (35) and Menton (06)
27.7°C in the streets of inner Paris (27.5°C at the top of the Eiffel Tower)
27.3°C in Nantes
27.2°C in Dinard (35)
26.9°C in Le Havre (76)
26.6°C in Boulogne sur mer (62) In addition, the first storms of degradation broke out on the tip of Finistère with powerful lightning strikes on the island of Ouessant, after yesterday’s 30°C. on Monday, dozens of monthly and absolute heat records were broken, mainly in the west of France.
Thus, with 36.7°C in Ploudalmezeau (29), the absolute record beaten yesterday is shattered today.
Nantes also broke its absolute heat record with 40.5°C, as well as Niort (40.3°C), Cholet (39.8°C), Saint-Nazaire (39.4°C), Vannes (39°C). C), La Roche-sur-Yon (39°C) or even Lannion (38.7°C).
There was also 29.5° on the island of Ouessant which could reach 30°C for the first time in its history.
In addition, there were also 41° in Biscarrosse, 38° in Bordeaux and 36° in Paris. Sunday July 17: At 6 p.m., the highest temperatures reached 42.1 in Bélis (33), 40.5 in Biscarrosse (40 ) and almost 40 in Bordeaux (33). The very hot weather reached Brittany with 35.2 in Brest (29) and 35.1 in Vannes (56). Evolution After the tropical night, this Tuesday, temperatures are beginning to drop across the Atlantic while the most intense heat will reach the Paris basin, the east and the center of the country. From Hauts-de-France to the Paris basin, in the Center and in the Grand-Est, 40°C could be reached and locally exceeded, and 36 to 38°C elsewhere. This heat will be accompanied by a moderate scorching wind in the afternoon, which can fan wildfires. Thereafter, from this Tuesday evening, this heat wave will gradually recede from the west, with a diffuse stormy development on the north. But this heat wave will persist for a few more days in the east and south-east where the alert will be extended. The drop in temperatures after this episode will be very relative with the persistence of high temperatures in France, but less excessive. The storms will set in between 8 p.m. to Limousin and western Auvergne. The strongest will burst from the Hautes-Pyrénées to the Gers, Haute-Garonne and Tarn-et-Garonne. Then, they will go up towards the central regions, losing intensity during the night, and in a rather scattered way. They could be quite marked in the first part of the night, with a risk of hail, gusts of wind and cumulative rain that could quickly reach 20 to 30 mm, but it will be quite localized. List of departments concerned