A first half of October on a dry diet
After a month of September with very heterogeneous precipitation, but with an average rainfall deficit of around 25%, this first half of October is marked by lastingly dry weather. Rainfall accumulations are very low in most regions. Only the far north, the east of the Paris Basin, the Jura and the Northern Alps were able to benefit from slightly more significant watering with 10 to 30 millimeters.
Rainfall totals from October 1 to 15, 2023 © La Chaîne Météo
Finally an improvement in rain this week
After lasting anticyclonic conditions during the first half of October, the weather situation is finally unblocking under the influence of a vast low pressure system establishing itself over Western Europe. After calm weather with an easterly regime on Monday and Tuesday, the weather deteriorates over most of the country between Wednesday and Thursday with the establishment of an unstable south to southwest regime. Rain or showers will arrive from the west and the south and will eventually cross the entire country. The rains will block the Cévennes for a long time, overflowing onto the Languedoc plain. Rainfall accumulations could exceed 200 millimeters, the equivalent of more than a month of rain. Heavy rain of a stormy nature will also end up affecting the PACA region at the end of the week with accumulations which could exceed 100 millimeters. Elsewhere, cumulative rainfall will be significant from Aquitaine to Berry and southern Burgundy with 50 to 80 mm. Elsewhere, cumulative rainfall will often be between 20 and 40 mm this week.
Total rainfall expected this week © La Chaîne Météo
The surface drought has spread to a large part of the country with this blocking anticyclone which has stagnated since the beginning of the month. This week will finally mark the return of more autumnal conditions with rainy spells which will cross most of the country. The surface drought, which is worrying for this time of year, will finally ease significantly this week. If this Monday, October 16, most regions were affected by very dry surface soils, the rainy improvement expected especially between Wednesday and next weekend will contribute to putting an end to this surface drought over most of the country. .
Significant improvement in surface drought © La Chaîne Météo
A slightly worsening groundwater situation
According to the latest BRGM bulletin dated October 1, the situation deteriorated between August and September since 66% of water tables were below monthly normals in September 2023 compared to 62% in August 2023. The 2023 low water level (highest level low water) is particularly late this year due to the long-lasting good weather in recent weeks. The start of groundwater recharge is therefore delayed this year. The rains that will fall this week will primarily serve to moisten the surface soils and the vegetation. They will undoubtedly still be insufficient to recharge the water tables.
State of groundwater as of October 15 © La Chaîne Météo
We see a very slight improvement this week since water restrictions concern 77 departments compared to 79 last week. There are nevertheless 52 departments in a state of crisis in at least one of their watersheds compared to 51 last Monday. Finally, 15 departments are at heightened alert level compared to 17 last week.
Water restrictions as of October 15 © La Chaîne Météo
Our seasonal forecasts for the months of November, December and January expect a month of November that will still be a little dry with wetter weather conditions in December and January.
2023-10-16 21:41:58
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