The snowflakes returned to the plains this Tuesday morning in part of northern France. This is only the first episode in a sequence of several days where the thickness on the ground could reach several centimeters in certain regions.
At the end of the night, snow showers affected certain areas in the north of Normandy such as Calvados and Hauts-de-France. A shower hit Tréon, in the Nord department.
Further south, in Amiens, in the Somme, it was necessary to exercise caution when traveling, even if ground handling was limited by the passage of vehicles.
The showers continued into the morning, as in Arras, in Pas-de-Calais.
When it comes to snow in the plains, forecasting is always difficult to establish precisely. The different factors coming into play such as temperature or the precise position of clouds are numerous and, above all, small variations such as a single degree of difference for example can transform snow into rain or vice versa.
Meeting between warm, humid air and cold air in the North
If, since the start of the week, Thursday seems to be the day likely to accumulate the largest quantities of snow on the ground in the greatest number of regions, the majority trend which emerges this Tuesday in the middle of the day is that the period going from Wednesday in the afternoon to Thursday in the morning, which is the most exposed.
The north of the country will find itself on Wednesday in an air mass conflict conducive to the formation of snow. Warm, humid air coming from southern Europe will come into contact with air of polar origin in the northernmost regions of France. The contact zone between the two will be favorable for snowfall, as shown in this representation provided by Keraunos, the French observatory for tornadoes and violent storms.
From eastern Normandy to Hauts-de-France, snowfall could be quite heavy from around mid-afternoon. They should also concern regions close to this sector. For the moment, Météo France is issuing a yellow alert (level 2 out of 4) due to the risk of snow and ice.
Orange vigilance in sight
This vigilance concerns the entire Hauts-de-France region, but also Seine-Maritime and Eure in Normandy, the Ardennes in the Grand Est region, as well as Yvelines and Val-d'Oise, the region Île-de-France is located on the edge of the area likely to experience snowfall. The meteorological organization is considering a move to orange vigilance (3 out of 4) “when the location of the most intense falls will be more precise”.
Among the different possible scenarios, The Weather Channel offers the following. The snow (in pink) affects Normandy in the middle of the afternoon on Wednesday, then reaches the entire north of the country at the end of the day and in the evening.
Some scenarios predict snow showers to continue overnight and into Thursday morning. At a minimum, the north of the country will be faced with ice and several centimeters of powder on the ground Thursday morning.
Up to ten centimeters on the ground
The weather channel estimates that the accumulation could often be greater than 5 cm in the affected area. The most exposed sector could be between Amiens (Somme) and Arras (Pas-de-Calais) with up to more than ten centimeters on the ground. It is however important to remember that the snow disturbance could pass a little further north or a little further south, thus affecting only the regions closest to the northern coasts of France in one case and Île-de-France more largely in the other.
This nuance is visible in the projections of two weather models, the German Icon and Arpège from Météo France. The first assumes a passage to the north of the country where the thickness of 10 cm on the ground would only concern a relatively narrow strip going from the coast of the Somme to the Belgian border.
The second focuses on a passage further south, encompassing a large half of Île-de-France. In this case, it is from Normandy to the Belgian border that the thickness would reach around ten centimeters.
Forecasting remains difficult for the future. But Météo France predicts further snowfall on Friday. These would affect “a possible axis going from Brittany/Normandy to Burgundy”.
