Why does the cold air in the north affect China and bring sleet?

The cold air in the north affects China. If it brings sleet weather, it will happen in winter when the temperature is low. Cold air meets warm air in the south, forming a cold front between cold and warm air. Warm air climbs along the front, and water vapor condenses when it meets cold to form rain and snow.

The front formed by the active movement of cold air mass to warm air mass is called cold front. Cold front is the most common front in China, and it can move all over the country. Because of the different configurations and moving speeds of the cold front and the upper trough, the distribution of clouds and precipitation near the cold front is obviously different, and some of them mainly appear behind the front; Others mainly appear in the front.

Cold front is the front produced when the cold air mass plays a leading role in the front movement and pushes the front to move to one side of the warm air mass. A cold front is what people often call a cold air front. It is Depth Charge with cold air heading south, and it is the most common weather system that affects China, especially in winter. Every few days in winter, a cold air invades the inland from northwest and north China. When the cold front crosses the border, it will be accompanied by the increase of northerly wind, the increase of air pressure and the decrease of temperature, which will sometimes cause rain and snow and even cause heavy rain in summer. Generally, after the cold front crosses the border, the local area will be controlled by cold high pressure, and the weather will become sunny.