The first fortnight of this month of December is marked by very cold air located in northern Europe, which might invade France from the middle of next week. But the reliability of this evolution is still very limited. Be that as it may, a strong north-south opposition should characterize this month of December, while a slow general warming trend will set in during the second half of the month. The end-of-year holiday period would be fairly mild but wet over the northern half.
Week of December 5 to 11: significant north-south contrast
This week’s predictability is particularly unreliable. France is affected by cold air located at the level of the English Channel while the depressions located on the Iberian Peninsula bring up mild air with frequent rainy periods. This contrast should end with a descent of generalized cold air at the end of the week and for the following weekend. The transition might give rise to snowfall in the plain, which should be specified.
The overall reliability can be estimated at 55%, which is limited, but in regional detail, this reliability is even lower to date.
Week of December 12 to 18: cold, especially in the north
Mid-December might be marked by widespread cold, quite brief in the south but longer in the northern half. The frost would then be quite marked, especially in regions with snow-covered soils, possibly in the center-east. In this context, the risk of snow in the plain is therefore present. The reliability of this evolution is moderate concerning the occurrence of this cold period, but remains to be clarified concerning the epiphenomena of snow in the plain. Rainfall will remain higher in the south and southeast than in the north of the country due to the Mediterranean depressions, which is consistent with the scenario proposed in our seasonal forecasts.
The overall reliability for a cold scenario seems to us close to 55%, but in the accuracy and the weather chronology, this reliability remains very low to date.
Week of December 19 to 25: towards a milder Christmas
The first week of the Christmas holidays might be calmer, with high pressures returning to the country, swelling once more from the south. Our country would then find weather that was sometimes foggy in the plains and sunny in the mountains. Despite everything, weak disturbances might circulate to the northwest with some rain. The air mass will soften, to pass above seasonal norms for this Christmas 2022. We might envisage a Christmas on the balcony in the south. The reliability of this evolution remains moderate and already corresponds to what we mentioned in the previous update.
Despite the distant deadline, the reliability seems moderate to us to tend towards this scenario, in its entirety.
Week of December 26 to January 1, 2023
The meteorological context would remain fairly mild over France, with, a priori, wet and moderately disturbed weather over the northern half, calmer and anticyclonic in the south.
In total, the average temperatures for this month of December might be within the seasonal norm, with a fairly marked north-south contrast. Precipitation would be slightly below the scale of France, except in the south-east where there will be excess around the Mediterranean. The first snowfalls on the plain might also be observed in the middle of the month, especially in the south and in the center. Fairly calm weather, but gradually milder, is currently expected for the end of the year period. This evolution seems moderately reliable to us.
