A powerful and durable low pressure rail
Synoptically, France will find itself under the direct influence of a very dynamic ocean current, stretching from Newfoundland to Western Europe. This low pressure rail, powered by an exceptionally powerful jet stream, is itself energized by the major cold wave underway in the United States, which reinforces thermal contrasts across the North Atlantic.
Result: a rapid succession of disturbances will cross the country, bringing repeated rains, but also a risk of strong winds, even stormy, depending on the trajectory and intensity of the depressions. This durable and repetitive nature constitutes one of the main warning factors.
European “monsoon” © LCM
Heavy rains on already saturated soils
The heaviest rainfall totals are expected on the western coast and especially Brittany, as well as in the Mediterranean regions, notably Languedoc and the Cévennes. However, these areas have already been heavily watered in recent days, with saturated soils and reactive waterways.
The repetition of precipitation clearly increases the risk of floods, sometimes rapid, and localized flooding, including for rainy episodes which, taken in isolation, would not be exceptional. In the Mediterranean, the context could also favor long-lasting rains, sometimes sustained, accentuating runoff.
A situation to monitor over time
More than the occasional intensity of the rains, it is their persistence that is worrying. In this type of configuration, hydrological risks occur over time, with a progressive deterioration of the situation over successive disturbances.
Next week will therefore require close monitoring, both for the risk of flooding and for possible episodes of strong winds associated with this very dynamic regime.
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