Change in weather at Christmas – things aren’t going well for the polar vortex

NExtremely cold weather is expected in the coming days. Although the sunny moments are increasing this Thursday and also on Friday, thick fog and high fog fields can also prevail and thus effectively cloud the sunshine (cloud radar). If that is the case, they move Temperatures barely above freezing point. However, if the sun comes out, temperatures can reach +6 degrees in predominantly dry weather.

Snow, sleet and rain on the Advent weekend

A low pressure front is approaching Germany on Saturday and will push itself over the cold air lying on the ground with milder air masses. Although the wind is picking up gusty over the north and at times with stormy gusts on the coasts, the wind remains unmotivated in the south. Precipitation is expected to begin over the northwest on Saturday afternoon, which will fall in liquid form at temperatures of +2 to +6 degrees. Further south there is no mixing and the main precipitation reaches Baden-Württemberg and Bavaria on the night of the third Advent, so that it reaches the middle altitudes short-term winter weather conditions can adjust. The temperatures subsequently rise and by Monday at the latest, with temperatures of +6 to +12 degrees, a snow cover below around 800 meters no longer plays a role. The weather itself will be slightly unstable and not very wintry until Tuesday. Sunny phases are possible from time to time when it is predominantly cloudy. If you want to know more precisely – weather December 2024.

The weather until the fourth Advent – the overall weather situation is changing

The weather maps above show what will be important in view of a white Christmas – the stability of the polar vortex. The high pressure zone between Canada and Siberia is shaking, which is an important signal.

High wave movement along the polar front

The increasing instability of the polar vortex leads to greater wave movement along the polar front, which can result in a meridional course of the base flow. The high will be able to dominate the weather over Germany until December 18th (Wed.), after which the wave trough will prevail until the fourth Advent and offers – in view of frosty holidays – a good foundation. At least the starting situation is significantly better than in previous years.

Wet cold weather

Before it can get cold, it has to be warm. The maximum temperatures are expected from December 17th to 19th at +8 to +14 degrees. Subsequently, a low pressure pushes from Iceland towards Scandinavia and on its back brings cooler air masses to Germany, which causes temperatures to drop to +4 to +8 degrees by December 21st and to +1 to +4 degrees on the 4th of Advent.

Falling snow line

With increasing wind and precipitation activity the snow line drops on the 4th Advent to 500 to 800 meters. Above approximately 600 to 900 meters, in addition to snowfall, a blanket of snow can also be expected to form. Below is a wet, cold, windy and dirtier Weather character to be expected.

The Christmas forecast – a hot ride on the wave

Right away – according to the Christmas trend of both forecast models The polar vortex no longer looks good until Boxing Day. It continues to destabilize and further high pressure systems are expected to move in. As far as what can be expected.

As instability increases, uncertainties also increase. Anyone who is on a Winter wonders at Christmas hopes, should pay attention to the fact that the high pressure center remains in the Atlantic. The problem, however, is not so much with the high pressure system, but rather with the change in the basic flow within the polar vortex, which releases another significant surge of polar air masses over eastern Canada onto the Atlantic shortly before the holidays. It is therefore quite possible that the blockade high on the Atlantic will shift eastward over Christmas – and thus over Germany, Austria and Switzerland.

Winter Christmas – that’s what’s important

So there are several parameters that change in the period from December 22nd to 24th (Christmas Eve) and can cause one or two surprises. Both prediction models show an unsatisfactory intermediate solution – a compromise, so to speak. With a strong to stormy wind, maritime air masses are carried into Germany. According to the Christmas forecast from the forecast models, temperatures will reach +0 to +5 degrees on Christmas Eve and +6 to +12 degrees on December 26th (Boxing Day).

How close the whole thing is can be seen in the following comparison with two control runs. Same starting point, slightly different basic parameters, what a festive snow landscape can still be made possible.

In a nutshell: Christmas days with snow?

No, the answer to the question of a white Christmas remains today. The scheme doesn’t really fit (yet), and the probability of a tipping frontal zone with a subsequent northwesterly orientation of the base flow is and remains the expected variant for the holidays.

What weather is likely

This becomes clearer in the temperature curve at an altitude of 1,400 meters. The forecast there is up to +6 degrees for December 19th. The temperature drops to -3 degrees by the time the presents are delivered on December 24th and to -2 to -4 degrees by Boxing Day on December 26th. For the lowland winter, altitudes of -5 to -7 degrees are a basic requirement, while -3 to -5 degrees are sufficient for the middle altitudes. And that sums it up very well today – a cold, wet Christmas over lower altitudes with wintry options from the middle altitudes onwards. What remains are the uncertainties, which can still cause one or two surprises. Let’s take a look.

Next update

• 8:15 p.m: Update of the Christmas forecast here