What is the explanation of Meiyu?

Explanation of Meiyu: Climate phenomenon of continuous rainy days.

Meiyu season is a warm and humid air flow in the Pacific Ocean brought by the southeast monsoon in June and July every year, which passes through the middle and lower reaches of the Yangtze River. Because it is the mature period of plums in Jiangnan, it is called "Meiyu", and this period is called Meiyu season. In the rainy season, the air humidity is high and the temperature is high, so clothes are easy to get moldy, so some people call the rainy season "moldy rain". After the rainy season, the weather began to be dominated by the Pacific subtropical high and officially entered the hot summer.

Formation conditions of plum rain

1. There are blocking high pressure or stable high pressure ridges in the middle troposphere at high latitudes in Asia, and the atmospheric circulation is relatively stable and rarely changes;

2. The westerly circulation in the mid-latitude area is gentle, and frequent short-wave activities provide cold air conditions for the Jianghuai area;

3. The western Pacific subtropical high has an obvious process of extending westward and jumping northward. The ridge line of the 500 HPA subtropical high is stable between 20 and 25 degrees north latitude, and the warm and humid air flow is transported from the edge of the subtropical high to the Jianghuai basin.