Unprecedented cooling detected in the upper levels of the polar vortex, but it is weak and incoherent. How is that?

Arab Weather - Data from NASA's computer simulations that monitor temperatures in the stratospheric polar vortex revealed that the upper levels of the polar vortex are experiencing record and unprecedented cooling according to the climate record since at least 1978, i.e. about 47 years ago, but the polar vortex is weak and incoherent, details and reasons at the end of the article.

Temperatures in the upper levels of the polar vortex reach below 80 degrees below zero.

According to the outputs of the computer simulation at the Arab Weather Center, temperatures in the upper levels of the polar vortex reach less than 80 degrees below zero. This cooling is considered record-breaking, historic and unprecedented according to NASA's climate record. The upper part of the polar vortex is located at an altitude of about 30 km above sea level and is called the stratospheric polar vortex.

What is a stratospheric polar vortex?

The atmosphere consists of several layers, and the second layer is the stratosphere (10 hPa) at an altitude of about 30 km above sea level. The air in this region is very dry and cold, especially above the Arctic Circle. As autumn approaches, the polar regions begin to receive less sunlight due to the tilt of the Earth's axis. This decrease in solar radiation leads to a rapid cooling of the stratosphere above the North Pole.

This cooling creates a large temperature difference between the poles and lower latitudes, and as the stratosphere continues to cool, the westerly winds surrounding the polar masses (normally) increase in speed, forming a circular system known as the stratospheric polar vortex. These strong winds trap cold air inland and separate the polar regions from the temperate regions.

Despite the extreme cooling of the polar vortex, it is weak and incoherent. How is that?

Despite the severe cooling of the polar vortex, it is weak and incoherent, due to the formation of areas of high atmospheric pressure. The polar high causes the polar vortex, in which the polar jet stream is active, to disperse and weaken, causing the direction of the jet stream to change from its normal behavior and to undulate greatly and rapidly. The jet stream is the fast air belt that separates the cold air in the North Pole 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 the areas of the middle 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 translates into the reason for the series of Atlantic storms that will recently affect various regions of northern and western Europe, specifically the Scandinavian countries, Ireland, and the United Kingdom, in addition to North America and southern Greenland, and whose activity is expected to continue during the coming period, God willing.

And God knows best.