“The stratospheric cold air body remains […] closed and the circulation of westerly winds around it is maintained. This should not change much until the end of December.
MeteoNews
This is also reflected in the forecast for wind conditions. Almost all models from the European Meteorological Service indicate persistent westerly winds. A truly drastic mixing of the upper cold air with the lower air layer is therefore unlikely to occur, and bursts of extreme cold air far to the south become less likely, according to MeteoNews.
Models and their limits
And what about beyond the next month? To answer this question, we can consult the current seasonal forecasts from the major weather services. What to keep in mind:
“This is not a concrete weather forecast, but a large-scale, long-term estimate of current and pressure patterns. […] This is just a gross trend!”
MeteoNews
The uncertainty factor is therefore high – weather forecasts are only really accurate for the coming days. However, long-term forecasts are improving; for example, they have made it possible to predict the scorching summer of 2022 quite accurately.
Meteorological institutes
Institutes and authorities such as the National Centers for Environmental Prediction (NCEP) or the US National Oceanic and Atmospheric Administration (NOAA) produce medium- and long-term forecasts for precipitation, pressure distributions and temperatures. In Europe, the European Center for Medium-Range Weather Forecasts (ECMWF) is considered the best reference for forecasts over a slightly longer horizon. But the German weather service or its French counterpart, Météo France, also identify longer-term trends.
The models
The models base their long-term forecasts on many variables within a highly complex system, for example the position and movement of the jet stream as well as different atmospheric pressure systems. The Enso (El Niño-Southern Oscillation) also plays a decisive role, even if it hardly concerns Switzerland and Europe. It describes the complex system of the South Pacific, which results in irregular variations in ocean temperatures and wind systems.
Seasonal forecasts
Atmospheric pressure
The European Meteorological Institute and the American Meteorological Institute estimate that the coming winter months will be marked by above-average atmospheric pressure over the Atlantic (also known as the Azores High).
Forecast of the deviation of atmospheric pressure from the long-term average (1993-2016) in Europe for the months of December, January and February.Image: ecmwf
The latest NOAA forecasts also predict very high atmospheric pressure in the Mediterranean region. The same is true, to a lesser extent, for a large part of the European continent. At the same time, northern Scandinavia appears to be experiencing unusually low atmospheric pressure.
What this could mean for the weather:
“According to these data, the trajectory of the depressions therefore seems, in many cases, to be located rather further north.”
In other words, major weather disturbances in the form of depressions accompanied by precipitation, which come from the “meteorological kitchen” that is the Atlantic, will tend to pass north of Switzerland during these winter months.
Precipitation
This distribution of atmospheric pressure should have repercussions on winter weather, particularly on precipitation. The American model in particular, but also partly the European model, predicts relatively much precipitation for northern Europe and relatively little for the south. Switzerland seems to fall right in between. Here, the trend and precipitation therefore looks like an average winter.
Forecast of the deviation of precipitation from the multi-year average in Europe for the months of December, January and February.Image: NOAA/tropicaltitbits
Temperatures
This is no longer a surprise, but rather the new normal: winters are all warmer than average. The same will almost certainly be true for the months to come.
Forecast of the deviation of the average temperature from the multi-year average in Europe for the months of December, January and February.Image: ecmwf
What differs from winter to winter, however, are the expected temperature “hot spots.” This winter, it seems that the temperature peaks will be located mainly in the north-east of Europe. On the other hand, writes MeteoNews, cold poles will become rare. And:
“This does not mean that there will not be colder phases with snow down to low altitudes from time to time, but like last winter, this should not be really lasting.”
MeteoNews
So what is the – cautious and provisional – conclusion to draw? Currently, weather models indicate (once again) that winter will be warmer than average. Both the state of the polar vortex in the near future and seasonal forecasts further suggest a low probability of long cold spells, at least until the end of the year.
Above average precipitation as well as significant weather disturbances are likely to occur in northern Europe, while below-average precipitation is more likely in the south. Precipitation in Switzerland should be average – but in the plains, due to (too) high temperatures, they should rather fall as rain than snow.
Translated and adapted from German by Léa Krejci
