France is under the influence of a mass of cold air descending from Northern Europe. At the same time, milder and more humid air comes from the southern Bay of Biscay and the Iberian Peninsula.
The disturbance in the ocean that opposes the cold air that is present in our country brings a period of wet and sticky snow in the Massif-Central and up to the hinterland of Languedoc. Snow is moving into the Rhône-Alpes region and the north of the PACA region this evening. As the altitude melts, freezing rain takes over from snow in areas of the Massif-Central. On Tuesday morning, the disturbance is moving south of Burgundy-Franche-Comté with light snowfall. From northern Auvergne to the Alps, precipitation continues in the form of freezing rain or snow.
At 9 pm, the snowy episode is general throughout the Massif Central. Snow sticks to the ground from a height of 300 meters on average. We have already measured 5 cm in Le Puy (43). This snow reaches Clermont-Ferrand, Saint-Etienne and Lyon where it starts to hold the ground at 0 to -2°C.
Snow reached the Rhone Valley, between Montélimar and Vienne with 0°C. It also snows from a height of 500 meters in the hinterland of the Var. This snow extends to the entire Rhône-Alpes with moderate intensity, sometimes to the bottom of the valley between Grenoble and Annecy, as well as north of Lyon.
At 18 o’clock, the snowfall continues a little more than expected in the Charentes and in areas where the temperature is between 0 and 1°C, such as in the Angoulême region. In the Massif Central, the waterfall is reinforced and falls from 300 m. These rains will continue to increase, in the next three hours, in the Lyonnais direction while reaching towards the Southern Alps. The first falls should affect the Rhône department, between 9 pm and 10 pm They will arrive at temperatures around -1°C.
At 15h, the disturbance came in the southwest with mixed rain and snow in the north of the Garonne, from Charentes to Lot-et-Garonne with +2° to +3°C. Rain replaces snow most of the time, but the north of the area, between Charente and Limousin, remains the risk of freezing rain overnight. Elsewhere, melting prevails at night.
at 12 o’clock, the snow episode hasn’t started yet. The first rains began in Aquitaine with the arrival of trouble.
Tonight, it continued to snow south of the Massif Central, with the rain/snow limit rising towards 1000 metres. In the Rhône Valley, the cold air is more resistant and snowfall or freezing rain occurs from Montélimar to the south of Lyon. Snowfall is moderate, but relatively permanent at very low altitudes in the southern Alps. Snowfall is less in the northern Alps.
Tuesday morning, with melting altitude, the risk of snow and freezing rain will disappear from the south of the Massif in the middle of the Rhône valley. Cold air can fight in the Inner Alps with snow down in the Alpine valleys. There will still be snowfall or freezing rain from the north of Auvergne to the north of the Rhône-Alpes region. They will also reach the south of the Bourgogne-Franche-Comté region.
Tuesday afternoonsome snowfall or freezing rain will still occur between the Jura and the Alps, but the disturbance will move eastwards over time and the rain will eventually move towards Switzerland and Italy.
At this stage of the winter season, we expect:
– heavy snowfall south of the Massif-Central : 20 to 30 cm in Ardèche and Lozère above 800 m
– several centimeters of snow to the plains in Auvergne-Rhône-Alpeswhich may cause traffic problems
– heavy, sticky snow which can cause damage to the electrical network and plants
– freezing rain causing traffic problems in areas not used to freezing conditions (especially in the Rhône Valley).