Climate Report | Temporary warming of the polar vortex leads to a break in the polar jet stream (details)

Arab Weather - Weather experts at the Arab Weather Regional Center are following up on the latest numerical computer modeling indications regarding the sudden and temporary warming in the stratospheric polar vortex, which, God willing, caused the formation of a region of high atmospheric pressure above the Arctic Circle, and its reflection on the behavior of the polar jet stream and its impact on global weather patterns in the coming period. Below is a detailed scientific report.

First: What is the stratospheric polar vortex and how does it build during the fall?

In detail, the atmosphere consists of several layers, and the "stratosphere" layer (10 hPa) is the second layer of the atmosphere 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 differential between the poles and lower latitudes, and as the stratosphere continues to cool, the westerly winds (normally) surrounding the polar masses 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. As fall continues into winter, the polar vortex becomes more stable and stronger, with the temperature differential between the poles and other regions intensifying.

Second: What is sudden stratospheric warming?

The stratospheric polar vortex is a large area of low pressure and strong winds that circulates around the North Pole in the stratosphere. The stratospheric polar vortex affects weather patterns in the Northern Hemisphere, including Europe, North America, and Asia. Sometimes, the vortex can become disturbed or broken up (due to a "sudden stratospheric warming" phenomenon), causing cold air from the North Pole to flow toward the mid-latitudes, which can cause severe cold spells.

Sudden Stratospheric Warming (SSW) is a weather phenomenon that occurs in the stratosphere, where temperatures rise suddenly and dramatically, sometimes by tens of degrees Celsius within a few days. This phenomenon directly affects the polar vortex, disrupting or even collapsing it, and causing significant changes in weather patterns in the regions below it.

Scientific Report | Tropical cyclones take a rare path and merge with polar air masses in the North Atlantic

Third: Sudden stratospheric warming causes the formation of a strong surface high over the North Pole.

Meteorologists at the Arab Weather Regional Center said that as a result of the weakness of the western polar winds above the Arctic Circle and the descent of polar air from the upper levels of the atmosphere close to the Earth's surface, a temporary stratospheric warming occurs in the Arctic region, which causes the formation of a strong high-pressure system above the Arctic Circle. As previously mentioned, the upper western winds are what contain the polar masses in the Arctic, and as a result of their weakness, they are unable to contain the polar air and keep it in its original home (the North Pole).

Stratospheric warming affects the polar vortex, causing changes in polar air distribution patterns, and is directly reflected in the movement of jet streams and weather patterns in various regions of the Northern Hemisphere. The high pressure caused by warming is expected to cause the dispersion of polar air masses, thus causing a break in the polar jet stream, causing the dispersion of polar air masses. Polar air masses are expected to be concentrated in the coming period over northern and western Europe, in addition to northeastern North America and Russia, where the aforementioned countries will be exposed to very cold polar waves and heavy snow with large thicknesses, with the bomb cyclone phenomenon expected to occur, especially in North America.

God knows best.