Strong temperature variations in the mountains: difficult conditions to expect on Thursday

France will find itself on Thursday at the center of a conflict of air masses, between the cold air which tumbles from the British Isles by the maritime polar flow, and the very mild air which rises from the southwest. This separation of these two air masses will take place via a depression which will pass from west to east during the day. The center-east will be at the heart of this conflict, with a battle between warm air and cold air which promises to be tough throughout this day.

A strong thermal variation over short distances.

In the center-east, this area will be at the center of a conflict of air masses, with rapid temperature variations, while precipitation will be heavy. You will therefore need to be vigilant when traveling this Thursday, especially if you go to an altitude of more than 400 m in these regions.

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Temperatures can be radically different over distances of only a few kilometers along a north-south axis, sometimes with differences of 5 to 6°C. Even now, it is still very difficult to accurately predict the areas affected by snow or rain. However, snow will be present in abundance above 800 m across the entire region.

Large fluctuation in the altitude of the 0°C isotherm

What really needs to be monitored is the variation in the rain-snow limit, and therefore in the altitude of 0°C (altitude to which you must go for it to freeze). This 0°C isotherm could vary by several hundred meters during this long day on Thursday. With abundant precipitation, one should not be surprised by the rapid change in the state of this precipitation.

It will also be necessary to monitor watercourses and the risk of flooding on certain slopes, between water from melting snow and rain alone. With the sudden arrival of mild weather at the end of the day on Thursday, the snow risks melting quickly below 700 m, but then temperatures should drop again during the night. In this configuration, the risk of icy conditions will be increased in areas where the snow has previously melted.

This situation must therefore be monitored closely, and the entire La Chaîne Météo team will be there to follow these events.