Weather alert: Remarkable rainy episode in Brittany

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Situation

The period of cold weather that began in early December ended with a generalized mild spell on Monday.
This general thaw is accompanied by a major disturbance which undulates more than 48 hours over Brittany until Tuesday, causing heavy rains. The average quantities expected are between 50 and 100 mm, with maximums between 100 and 130 mm, i.e. an average of 3 weeks to 1 month of rain, which promises to be remarkable.

In a context of heavy seas with southerly waves of 3 to 4 m and strong south-westerly winds up to 90 km/h in gusts, the flow of rainwater could be hampered on the south coasts of Finistère and Morbihan and cause flooding of rivers (Odet, Aulne, Blavet, Laïta) causing overflows or flooding.

Observation

This Monday

At 9 a.m., the sustained rains continued from the Gulf of Morbihan to northern Brittany with moderate intensities between 2 and 4 mm/h. The southwest wind is blowing strong with gusts on the coast reaching 70 to 95 km/h. Over the last 24 hours, it has fallen on average 40 to 60 mm, with up to 64.6 mm in Coray (Finistère), 71.9 mm in Ploërdut (Morbihan), 75.2 mm in Kernascléden (Finistère) and 80 .6 mm in Bannalec (Finistère).

Evolution

Here are the characteristics of these bad weather in Brittany
A lull occurs this morning and lasts all day, hence the passage on yellow alert for the 3 Breton departments. A new salvo is however expected this evening and next night. Again, up to about 2 weeks of precipitation may fall and will add to existing accumulations. Locally, the accumulations will exceed 150 mm of water in the center of Finistère and Morbihan in 48 hours. In a context of strong seas with southerly waves of 3 to 4 m and strong south-westerly winds at 90 km/h, the flow of rainwater could be hampered on the south coasts of Finistère and Morbihan and cause flooding of rivers (Odet, Aulne, Blavet, Laïta) causing flooding.

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