Scientific report: The weakness of the polar vortex and the Arctic high and their relationship to the cold wave in America and the stability of the weather in the eastern Mediterranean

Arab Weather - The polar vortex is known as an area of low atmospheric pressure and very cold temperatures that revolves around the North and South Poles and is characterized by strong wind rotation.

The polar vortex varies from year to year, as it is strong and coherent in some seasons and rotates regularly, while it is weak and controlled by the polar highlands and weakens it in some years, as is the case in the current winter season.

What is the Arctic High?

The Arctic High is a region of high atmospheric pressure that forms over the North Pole in some seasons as a result of the great heating caused by solar radiation falling on the Arctic region, which leads to an increase in the temperature of the atmosphere there and a region of high atmospheric pressure or what is known as the Arctic High is formed.

How does the polar high weaken the polar vortex?

The polar high acts as a dispersant of the polar vortex in which the polar jet stream is active, causing the jet stream to change direction from its normal behavior and become very undulating and rapid. The jet stream is the fast air belt that separates the cold air in the Arctic from the warmer air in the southern regions.

The dispersion of the polar vortex or the change in the direction of the polar jet stream causes it to move away from its original home where it is naturally active, which leads to it undulating to areas of medium and perhaps lower latitudes, which weakens its movement and leads to it remaining in those areas for a long time before the pole rebuilds itself. The map below shows an example of the strength and weakness of the polar vortex:

This image or behavior in the movement of the jet stream leads to the sorting of extreme weather patterns in some countries of the world and stable weather in other areas in the northern hemisphere.

The relationship between the weakness of the polar vortex, the Arctic High, the cold wave in America, and the stability of the weather in the eastern Mediterranean

Experts at Arab Weather said that if the polar vortex holds together, it will be strong and regular, keeping cold air masses confined to the polar regions, and this maintains the regular behavior of the polar jet stream.

While if the polar vortex is weakened or divided due to disturbances such as the formation of the Arctic High, this leads to cold air masses rushing towards the middle and lower latitudes such as North America, Europe and Asia.

As an example of what is happening now with the weakening of the polar vortex, the United States of America is affected by a record cold wave due to a large part of the polar vortex rushing towards it, while a sub-polar mass divided from the main polar vortex is heading towards parts of western and central Europe, while the high pressure system is deepening towards the countries of the eastern Mediterranean and the weather is stable there.