what is this “weather bomb” that will hit Europe with gusts of up to 200 km/h?

This is the first named storm of 2025. And it promises to be (very) violent. She was “baptized” Éowyn (from the name of a character in the novel The Lord of the Rings by the British writer JRR Tolkien) by the Met office, the British national meteorological service, this Tuesday January 21, 2025.

And it should seriously shake the British Isles between this Thursday January 23 and Friday January 24, and to a lesser extent a large part of the west and north of France.

Wind gusts of more than 180 km/h in Ireland?

Winds of more than 150 km/h and even 180 to 200 km/h off the coast of Ireland are modeled on the other side of the Channel. The English and Irish weather services are warning of “risks of devastating wind gusts”.

In France, on the fringes of this system, gusts of more than 100 km/h in the west of France, mainly on the coasts, are anticipated as well as very strong swells off the coast of Brittany. And a lot of rain.

“This is a weather bomb or explosive cyclogenesis
», explains to actu.fr meteorologist Yann Amice, because the pressure drop will be well above 24 hectopascals in 24 hours between this Thursday January 23 and Friday January 24. A drop of 44 hPa in 24 hours, from 988 to 944 hPa, is anticipated.

A depression that will “deepen” very violently

This term is used to designate a depression which “deepens” violently, that is to say which develops within a few hours, after the encounter of cold air with a mass of warmer air, resulting in a significant drop atmospheric pressure. Which generates a powerful low pressure area with stormy gusts of wind.

Off the coast of Ireland, the atmospheric pressure will therefore be around 940 hectopascals, “which is almost a record”, comments on actu.fr meteorologist Guillaume Séchet.

After a long period of quiet time

This weather phenomenon comes after a long period of calm and anticyclonic weather, while the jet stream, a powerful upper-altitude wind axis, quickly revived from west to east across the North Atlantic.

It plays a fundamental role in the genesis and development of these low pressure systems, and in the way in which they then move across the Atlantic, often towards the British Isles and north-west Europe.

It is the current American cold wave which will infiltrate the northern Atlantic and create this strong thermal contrast.

More storms to come?

These strong winds at altitude above the ocean could reach more than 400 km/h this week, “giving very favorable conditions” to the development of gales or storms, for several days, warns now and already Yann Amice.

If this storm Éowyn will mainly hit Northern Ireland, the north of England, the northwest of Wales and the west of Scotland, and to a lesser extent the west of France, meteorologists already have another low pressure system in their sights. This is located further south this time, immediately off the coast of Brittany, and could well bring a serious blow to France between this Sunday January 26 and this Monday January 27, 2025.

“In this context of a very strong jet stream over the Atlantic, we are entering into greater vulnerability to this type of phenomenon. The engine is in place for the generation and intensification of successive low pressure systems, between this Sunday January 26 and the beginning of next week,” warns Yann Amice.

Even if the deadline is still far away and this context of strong instability makes precise forecasts difficult at this stage.

Follow all the news from your favorite cities and media by subscribing to Mon Actu.