Reasons for the formation of plum rain

Meiyu weather is mainly caused by blocking high pressure or stable high ridge in the middle troposphere in higher latitudes of Asia, and the atmospheric circulation is relatively stable with little change. At the same time, the westerly circulation in the mid-latitude area is flat, and frequent short-wave activities provide cold air conditions for the Jianghuai Basin.

At the same time, the cold air condition causes the western Pacific subtropical high to obviously extend westward and jump northward, the ridge line of the 500 hPa subtropical high is stable between 20 degrees and 25 degrees north latitude, and the warm and humid airflow is transported from the edge of the subtropical high to the Jianghuai Basin. Under this circulation condition, Meiyu appears, often accompanied by southwest vortex and shear line, and the mesoscale system is active on Meiyu front.

Extended data

rainy season

The beginning date of plum rain is "entering plum" and the end date is "leaving plum". Generally speaking, the higher the latitude, the later the meiyu begins. Plum blossoms in Taiwan Province Province are in full bloom in mid-May and mid-June. The average lunar calendar in the middle and lower reaches of the Yangtze River in China enters Mei in mid-April and leaves Mei in early May every year.

Typical plum rains generally "enter plum blossoms" in the middle and late June, and bloom in early to mid-July. Meiyu refers to the rainy days before plum blossom, which generally starts in mid-April and lasts for about half a month.

Baidu Encyclopedia-Meiyu Season

Baidu Encyclopedia-Meiyu