Of
Tuesday October 8 at 11:00 au
Thursday October 10 at 9:00 a.m.
Situation
The stormy episode in the south-east continues until the end of the afternoon from the Alps to the Côte d’Azur and Corsica, with risks of runoff especially in hilly areas. Then, improvement is rapid at the end of the afternoon.
Then, a new episode of bad weather will set in this Wednesday morning with the arrival of heavy, lasting rain as ex-tropical storm Kirk approaches. The accumulations promise to be notable in the regions going from Poitou-Charentes to the north-eastern Paris water basin until Thursday morning, falling on soils already saturated with water. Floods are likely as well as a general rise in the watercourses of these catchment basins (Seine upstream in particular).
We expect widespread accumulations of 30 to 40 mm, with peaks between 50 and 70 mm in 24 hours, the equivalent of 3 weeks of precipitation for these regions.
Finally, the winds will strengthen as the Kirk depression passes, between Wednesday evening and Thursday morning, which will circulate overnight from the Charentes to Luxembourg. An axis of strong winds, at the strong gale stage), will follow this trajectory with probable gusts between 80 and 100 km/h inland, peaks at 120 or even 130 on the coast and in the mountains. Gusts of 150 km/h are likely on the Pyrenean ridges.
Note that the tidal coefficients are low (around 40), limiting the risk of coastal submersion, but a moderate surge may be felt at high tide on Wednesday evening between the Pertuis Charentais and the Gironde estuary.
This episode will last from Wednesday morning to Thursday morning for rain, and from late Wednesday afternoon to early Thursday morning for strong winds.
Observation
This Tuesday at midday
The rains continue in a sustained and widespread manner from Franche-Comté to the Alps, while there are more occasional storms and showers over Corsica and the Côte d’Azur.
In 24 hours, we were able to record up to 114 mm in Haute-Loire, 106 mm in the Loire, 100 mm in Saône-et-Loire and 90 mm in Jura.
This Tuesday at 9 a.m.
Sustained rains affect the center-east, the Cévennes and the PACA region. The highest intensities of rain concern Provence-Côte-d’Azur and the Cévennes. Sustained rains also persist in the center-east. Total rainfall reaches 100 to 150 millimeters on the heights of the Cévennes and locally 200 m in the Grand-Combe sector in Gard. Remarkable rainfall totals concern Burgundy-Franche Comté with 75 mm in Arc-et-Senans (Doubs) and 100 mm in Branges (Saône-et-Loire).
Evolution
This Tuesday in the southeast: the episode weakens in the afternoon
Rainy intensities begin to decrease at midday but during storms, intensities can still be sustained in the Alpes-Maritimes. Then, the improvement will be rapid at the end of the afternoon. However, be careful of the reactions of watercourses and mountain torrents, and of the delicate traffic conditions on the secondary road network (rockfalls, landslides).
Heavy rain Wednesday:
A lasting and sustained rainy episode begins early in the morning from Pays de la Loire to the Ardennes via Ile-de-France, particularly in its southern part. It should be noted that there is still uncertainty about the precise zonation of the heavily rainy axis, which may occur further south or further north of it.
The heaviest rain falls in Poitou-Charentes from 5 p.m. to 10 p.m., then in the Center and the Paris basin rather from 6 p.m. to 1 a.m., then from 10 p.m. to 3 a.m. Thursday for the northeastern quarter . These rains will be heavy during the night as they are accompanied by a strengthening wind (80 km on average). Traffic conditions will therefore be difficult during the night from Wednesday to Thursday.
Strong gale and stormy gusts
In connection with the passage of the Kirk depression across France, the winds are strengthening over the Atlantic arc from this Wednesday afternoon, then will cross all of France towards Lorraine during the night from Wednesday to Thursday. Furthermore, all the mountains will be subject to stormy winds at altitude, especially in the Pyrenees, which can go down to the foothills.
– The wind picks up quickly on Wednesday afternoon on the Aquitaine coast and the west of the Pyrenees. Gusts between 100 and 110 km/h are expected on the coast, up to 150 in the high mountains. These strong winds spread in the evening throughout the southwest and the central massif (very degraded weather conditions at altitude in Auvergne).
– Night from Wednesday to Thursday:
strong winds (80 to 100 km/h at peak) progress rapidly in the Centre, Burgundy (heights of Morvan), Franche-Comté (in particular the Val de Saône), then the Lorraine plateaus. Strengthening is expected between the Côte d’or, Haute-Marne and MArne where gusts between 100 and 110 km/h are possible.
– Thursday morning:
The development is rapid: rain and gusty winds are evacuated towards Luxembourg and Germany. From 6 a.m., calmer, cooler and variable weather returns to all of these regions and the alert can be lifted.
On the other hand, the rains could block again on Thursday in the Jura and the Alps, which could justify an extension of a yellow level alert for rains.
