Causes of large-scale snowfall in Yunnan in recent two days

Celia, the cold air is heading south. Commonly known as Siberian cold current.

Mongolia-Siberia is the coldest place in the northern hemisphere in winter, and the atmosphere cools, contracts and sinks, forming the strongest and widest high pressure in the northern hemisphere. The center of high pressure is located in the high pressure area of Siberia and Mongolia, and moves eastward in winter and spring. The weather in the area controlled by this high pressure is fine and cold. Its high-pressure ridge often extends to the north of China, and the strong cold northwest airflow often forms cold wave weather when it goes south, so it is usually called Siberian cold current.