Why did the temperature in the north suddenly drop significantly?

This wave of cold air is divided into three paths, entering from the northwest, central-south and northeastern Inner Mongolia respectively. Then these three waves of cold air flow to the central region, and finally hit most of China directly southward. The impact is that the cold air moves rapidly southward, forming a "rapid southward movement" pattern, such as in Guangdong and Fujian. The warmth in Hainan also began to cool down sharply at the beginning of this month. On the other hand, the situation in the northern region is more serious. After the cold air enters the north, the temperature in the north will drop sharply, generally between 10~15~84451 in a day. Especially in the northwest and northeastern regions of China. Because it is already very cold in the north, after the cold air passes, the temperature drops sharply, like falling into an "ice cave."

Rainfall is the main form in southern China. The combination of rain and low temperatures means the humidity and cold will be more severe in the south. It may start to snow in northern areas, especially Inner Mongolia and Northeast China, and even in areas such as the Middle East of Inner Mongolia, Heilongjiang, Jilin and Liaoning. Speaking of this, many friends will be worried that the storm in the Northeast will once again cause difficulties in grain transportation.

The subtropical high pressure in the northern hemisphere has a significant impact on China's summer and autumn climate. Summer heavy rains in Henan and autumn heavy rains in Shanxi are related to the super strong subtropical high, but the subtropical high basically retreats from the mainland in winter. Due to the high pressure, the air will flow from here to the low pressure area, and two airflows will separate from the subtropical high pressure area, one going south and the other north.

Westerly winds will also encounter cold air from the polar regions. These cold air will be forced to lift under high pressure, causing updrafts and forming a low subpolar pressure zone. The polar vortex and the outer westerlies are trapped to some extent in the cold air at high Arctic latitudes, so it cannot move south easily. When the temperature in the Arctic is low and the pressure difference is large, the polar vortex and the western region will be relatively strong, nearly circular in shape, relatively small in scope, and have a strong blocking effect on cold air.

Once the Arctic temperature rises, the polar vortex will be relatively weak, its shape will become irregular, and it will even split into two parts, one in North America and the other in Siberia. The West Belt also often wobbles. The warm peak in the southern high temperature area may rise northward and push towards the Arctic. Under the attack of the heat peak, the polar vortex containing a large amount of cold air was forced to move southward, and the cold air directly reached China, forming a strong cold wave.

As we have already said, La Niña is different from El Niño in that it does not change the climate but increases the intensity of extreme weather. In other words, when La Niña occurs, it makes the climate more extreme. For example, it will make cold air activities more frequent and make the cold more intense.

So from this perspective, this winter may be colder