It is a phenomenon known as "omega-block", which appears when high pressure fields arise. They are important during the transition from summer to winter, because they take care of equalizing the temperature between tropical and polar regions.
But sometimes omega-block occurs in the middle of summer or winter.
When meteorologists hear this term, they usually know they have a lot of work ahead of them. Omega is persistent and stable - currently a high pressure field is held over central Europe, "fenced" by low pressure fields over the North Atlantic and the east of the continent.
The weather map then closely resembles the last letter of the Greek alphabet, which is how the phenomenon got its name.
The sun for some, the rain for others
The consequences are colorful. In the center of the block, for example in Germany, there is a Michaelmas summer because low pressure fields pass far, over the Mediterranean.
But the southern European peninsulas, the Pyrenees, the Apennines and the Balkans, have experienced epic rains as a low pressure field persists over them.
Colder air from the north collides with hot Mediterranean air, sea evaporation supplies the low pressure field with additional strength, storms and local showers follow.
After a long dry summer, the cracked earth is unable to absorb these water masses. The fires also previously consumed a lot of vegetation that normally holds water. The result is devastating floods and landslides.
More and more extreme
Meteorologists say that such "blockades" are becoming more common. Because of them, rain-bearing western winds find it increasingly difficult to find their way to Central Europe.
It is changing the circumstances in the heart of Europe. Because we are used to high pressure fields being created closer to the ground, but then being blown away by westerly winds in the direction of the Earth's rotation - that is, from west to east. In Central Europe, this meant moderate temperatures with alternating sunny and rainy days.
Omega-blocks cannot be directly linked to climate change but to short-term atmospheric conditions. But climate change can affect the frequency and strength of certain atmospheric phenomena.
It is hard to say how long this block will last, but the forecast for the Balkans is still bad. Meteorologists say that it is not until the beginning or end of next week that Atlantic low pressure fields could change conditions.
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