After the cold drop, Omega: This phenomenon that explains the weather forecast for the next few days

The current weather formation in Europe will be banned until the end of August, or perhaps even the beginning of the school year. This situation will always bring bad weather to the countries of Central Europe, while the weather will be milder in Western Europe, and thus France, despite the gray temperatures. Explain the causes and consequences of this development, especially what kind of weather you can expect in our country.

Fairly good weather is expected in France for at least 8 days, to the delight of vacationers at the end of August. However, we will notice local shades of gray in the northeast as thunderstorms erupt in the mountains, especially in the Southern Alps. Temperatures will sometimes be lower than seasonal averages north of the Loire, but summer is in the south of the country.

Weather block in “Omega”

The condition we’re seeing this week is called, in meteorological parlance, “omega occlusion,” from the Greek letter Ω which resembles the meandering made by a jet stream at an altitude. In fact, the jet stream creates atmospheric circulation by controlling air masses, depressions and counter-eddies, in generally linear and series motion. However, sometimes the jet stream slows down, forming meanders like a low-flowing river. These meanders can be blocked, as they are nowadays, resulting in freezing weather.

Weather conditions will be banned for the next eight days over Europe. The weather will be disrupted in central Europe, while conditions will be dry with varying temperatures over France. All this is due to the high pressure system prohibited over the British Isles. pic.twitter.com/Mh4Qu4FMau

– Weather Channel (@lachainemeteo) August 23, 2021

Sometimes the consequences of severe weather

You should know that the mass of high pressure “omega” also obscures everything around you, such as the surrounding depressions. These obstructions can cause severe weather events when they occur, depending on the regions involved, because they are long-lived. This summer we have seen many different obstacles and dire consequences. This phenomenon occurred in late June and early July in western Canada: a mass of hot air found itself permanently registered, causing an unprecedented heat wave and drought in British Columbia and neighboring countries. Also in June, another blockage occurred in Western Europe, trapping a cold drop in the Benelux and Germany, causing extraordinary flooding in these areas. This also happened in August in the Mediterranean, which led to the appearance of the “thermal dome” that we were talking about.

What will happen in Europe in the next few days?

So far, the high pressure mass in Omega has stabilized on the British Isles. The warm air blows toward Iceland, where it is temporarily warmer than northeastern France, around 25°C for a few days. At the same time, very fresh air from Scandinavia descends over Central Europe and the Benelux countries. Over central Europe, this fresh air will lead to a wide depression called ” cold drip ‘, with stormy rain in anticipation. Countries ranging from Poland to Germany, Austria and northern Italy will be affected by torrential and lasting rains until Sunday, raising fears of flood risks. France, which is under the influence of the anticyclone, will benefit from generally calm and pleasant weather, with a variation in temperatures between the northeast, which is rather cool for the season, and the south, which is subject to summer temperatures. Apart from the generally dry weather, this blockage will not have a direct impact on our country.

The danger of bad weather in the coming days in Central Europe 🌧️ In fact, a new cold drop, descending from Scandinavia, will be prevented from Wednesday to Sunday from Poland to Germany, Austria and northern Italy: floods must be feared. pic.twitter.com/BNuSJSCrAr

– Weather Channel (@lachainemeteo) August 24, 2021

What would have happened if the blockage had been positioned differently?

It is interesting to note that this type of blockage in summer only occurs 20-30% of the time, and is therefore very rare. But when that happens, the consequences can be dire. Thus, like the June heat wave in British Columbia, the great European and French heat wave of August 2003 originated in this kind of formation. Omega was located more in the center of Europe, which brought hot air to France, and as a result, there was a historical heat wave for more than 10 days in a row.

If rare in summer, this formation is more frequent in September and October, resulting in perpetual good weather over France with a “beautiful late season” feel. However, this causes the humid Mediterranean air to rise in the southeast of our country, resulting in the occurrence of Sevin rings. When this type of blockage occurs in winter, it is responsible for dry weather with a lot of mist and low clouds in the plains, while it is pleasant and temperate in the mountains. In this case, there is no snow, which is hopeless in winter sports resorts. Finally, when, in winter, the blockage falls on the side of the North Sea or Scandinavia, as it is now, it is responsible for massive cold waves descending from the Arctic, as during the great winters of the twentieth century.

As we can see, such blockages are always accompanied by noticeable meteorological consequences and indicate a temporary weakening of the jet stream. If these formations have occurred frequently in recent years, there is no indication that they are associated with contemporary global warming, noted Robert Vattard, a researcher at the Laboratory for Climate and Environmental Sciences (LSCE), in this to interview.