From Wednesday November 1 at 6:00 p.m. to Thursday November 2 at 6:00 p.m.
Complete live weather forecasts by telephone at
3201*
Situation
In the middle of a vast low pressure system which encompasses the entire North Atlantic and western Europe, a depression, named Ciaran, deepens Wednesday morning between Newfoundland and Brittany. Driven by a powerful high-altitude jet stream at nearly 300 km/h, this depression quickly crosses the Channel basin between Wednesday evening and Thursday while continuing to deepen up to 955 hPa.
This very deep depression causes a storm between Wednesday evening and Thursday over a large northwest quarter of France, with winds of nearly 150 km/h on the coasts, and 20 to 30% more on the capes, coasts and exposed islands and 90 to 110 km/h inland. It is in Finistère and in Manche as well as in Côtes-d’Armor that the wind is expected to be the most violent with gusts of nearly 170 km/h, which is why these 3 departments have been placed in RED ALERT (maximum level) by our services.
In the Atlantic and the English Channel, the sea becomes big to enormous with waves of more than 10 meters in northern Gascony. Despite falling tidal coefficients (70 Thursday), these values will however be largely sufficient in view of the surge and swell expected to cause significant marine submersion phenomena at high tide.
Observation
In the middle of the day on Tuesday, storm Ciaran responsible for the bad weather is located off the coast of Labrador. Caught in a very powerful jet current at nearly 300 km/h at an altitude of 9,000 meters, it began digging at 1,000 hPa near its center. By Wednesday evening, it will cross the entire Atlantic at nearly 120 km/h.
Evolution
Here is the chronology and characteristics of this storm
From Wednesday evening, the wind will strengthen very suddenly from Pays de la Loire to Brittany up to Cotentin with winds reaching 120 to 150 km/h along the seaside and 100 to 120 km/h in Breton lands. It is in Finistère and Cotentin that the situation promises to be the most dangerous with gusts which could very locally reach 170 km/h.
During the night from Wednesday to Thursday, with the entry of the depression into the Channel basin, winds of nearly 100 km/h will spread throughout the west and north of the country, up to the Paris basin, going up towards Champagne and the North -Pas-de-Calais. Along the seaside, the gusts will be more violent and could approach 130 to 140 km/h with a 20% higher risk on exposed capes, coasts and islands.
Thursday morning, the neighboring regions of the Channel will remain exposed to violent gusts of nearly 120 km/h with speeds 20 to 30% higher occasionally under stormy squalls. Inland, the wind will weaken, but the gusts will remain strong at nearly 90 km/h north of Paris and even 110 km/h on the hills of Artois.
Thursday afternoon, Storm Ciaran will shift towards the North Sea and the wind will weaken in Brittany while it will remain violent between the Alabaster coast, the Opal coast and Dunkirk with gusts still higher than 110 km/h as well as on the hills of Artois.
During the night from Thursday to Friday, while the wind will calm down in the north, the situation will need to be monitored in the southwest with a minimum low pressure which will circulate from the Aquitaine coast to the Pyrenees with winds which could reach or exceed 100 km/h. Then FridayCorsica will in turn be hit by violent winds of nearly 150 km/h.
In the Atlantic and the English Channel, the sea becomes big to enormous with waves of more than 10 meters in northern Gascony. Despite falling tidal coefficients (70 Thursday), these values will however be largely sufficient in view of the surge and swell expected to cause significant marine submersion phenomena at high tide.
As Storm Ciaran passes, heavy rain will occur in Brittany. Accumulated precipitation could reach 30 to 50 mm inland between Wednesday evening and Thursday afternoon. These heavy rains risk causing reactions in rivers whose levels are already high currently, increasing the risk of flooding.
Due to this high activity, all our teams are mobilized to monitor this storm as closely as possible with hour-by-hour monitoring of the situation starting Wednesday morning.
List of departments concerned
- 02 -Aisne
Wind – Significant Risk
- 14 – Calvados
Wind – Orange Alert
- 16 – Charente
Wind – Significant Risk
- 17 – Charente Maritime
Wind – Significant Risk
- 18 – Dear
Wind – Significant Risk
- 22 – Côtes-d’Armor
Wind – Red Alert
- 23 – Dig
Wind – Significant Risk
- 27 – Eure
Wind – Orange Alert
- 28 – Eure-et-Loir
Wind – Significant Risk
- 29 – Finistère
Precipitation – Significant Risk
Wind – Red Alert
- 33 – Gironde
Submergence – Significant Risk
- 35 – Ille-et-Vilaine
Wind – Orange Alert
- 36 – Indre
Wind – Significant Risk
- 37 – Indre-et-Loire
Wind – Significant Risk
- 40 – Landes
Submergence – Significant Risk
- 41 – Loir-et-Cher
Wind – Significant Risk
- 44 – Loire Atlantique
Wind – Orange Alert
- 45 – Loiret
Wind – Significant Risk
- 49 – Maine-et-Loire
Wind – Orange Alert
- 50 – Sleeve
Wind – Red Alert
- 53 – Mayenne
Wind – Orange Alert
- 56 – Morbihan
Wind – Orange Alert
- 59 – North
Wind – Orange Alert
- 60 – Oise
Wind – Significant Risk
- 61 – Orne
Wind – Orange Alert
- 62 – Pas-de-Calais
Wind – Orange Alert
- 64 – Pyrénées-Atlantiques
Submergence – Significant Risk
- 72 – Sarthe
Wind – Orange Alert
- 75 – Paris
Wind – Significant Risk
- 76 – Seine-Maritime
Wind – Orange Alert
- 77 – Seine et Marne
Wind – Significant Risk
- 78 – Yvelines
Wind – Significant Risk
- 79 – Two Sevres
Wind – Significant Risk
- 80 – Sum
Wind – Orange Alert
Submergence – Significant Risk
- 85 – Vendée
Wind – Orange Alert
- 86 – Vienna
Wind – Significant Risk
- 87 – Haute-Vienne
Wind – Significant Risk
- 91 – Essonne
Wind – Significant Risk
- 92 – Hauts-de-Seine
Wind – Significant Risk
- 93 – Seine-Saint-Denis
Wind – Significant Risk
- 94 – Val de Marne
Wind – Significant Risk
- 95 – Val d’Oise
Wind – Significant Risk