Causes of plum rain

The main reason for the formation of Meiyu weather is that there is blocking high pressure or stable high pressure ridge in the middle of the troposphere in the higher latitude areas of Asia. The atmospheric circulation is relatively stable and less changeable. At the same time, the westerly circulation in the mid-latitudes is flat and frequent shortwave The activities provide cold air conditions for the Yangtze-Huaihe River Basin.

At the same time, cold air conditions caused the western Pacific subtropical high to have a significant westward and northward jump. The 500hPa subtropical high ridge was stable between 20 degrees and 25 degrees north latitude, and warm and moist air flow was transported from the edge of the subtropical high to Jianghuai River Basin. Under such circulation conditions, Meiyu appears, often accompanied by southwest vortices and shear lines, and mesoscale systems are active on the Meiyu front.

Extended information

Meiyu season

The day when the plum rain begins is "into the plum" and the day when it ends is "out of the plum". Generally speaking, the higher the latitude, the later the rainy season starts. In Taiwan, plum blossoms begin around mid-May and bloom in mid-June. In the middle and lower reaches of the Yangtze River in China, on average, plum blossoms begin in mid-April and bloom in early May.

Typical plum rain generally begins in mid-to-late June and blooms in early to mid-July. Yingmeiyu refers to the rain before the plum blossom season, which usually starts in mid-April and lasts for about half a month.

Baidu Encyclopedia-Meiyu Season

Baidu Encyclopedia-Meiyu Season