Why did it suddenly rain so heavily in Zhengzhou?

The sudden rainstorm in Zhengzhou is mainly related to the stable atmospheric circulation situation, sufficient water vapor conditions, favorable terrain conditions and strong convection.

Here, we need to understand the conditions for the formation of heavy rain first. The formation of a rainstorm requires the following three conditions, all of which are indispensable:

(1) Sufficient water vapor conditions

(2) A strong upward trend

(3) favorable terrain conditions

Then let's talk about the relationship between the rainstorm in Zhengzhou and these three conditions.

First of all, there are two main sources of sufficient water vapor for heavy rain in Zhengzhou. One is that the atmospheric circulation situation is stable, which leads to the transportation of water vapor to Zhengzhou, and the other is the water vapor caused by the formation of typhoon "fireworks".

Corresponding to the advance of the annual rain belt (South China-Jianghuai-North China), July and August are the rainy seasons in North China. In July and August every year, the western Pacific subtropical high and continental high remain stable in the Sea of Japan and northwest China. In this way, the low-pressure system between them is stably maintained in Huanghuai area, which leads to a relatively stable water vapor supply in the central and western parts of Henan Province in July.

At the same time, in mid-July, Henan is just on the edge of the subtropical high in the northwest Pacific, and the southeast airflow can also bring some water vapor transportation to Henan to some extent.

Finally, on June 5438+08, the typhoon "Fireworks" came into being and gradually moved inland. Affected by the airflow around the typhoon, a large amount of water vapor was transported to the inland of China, which also provided a strong water vapor supply for this rainstorm.

In addition to water vapor supply, as mentioned above, Henan is located in the marginal area of the western Pacific subtropical high, which will also make Henan's convective instability energy sufficient. Therefore, the occurrence of rainstorm has greater potential unstable energy. This is also an important condition for the instantaneous precipitation of this rainstorm in Henan to reach 200 mm.

In addition to the potential unstable energy at the edge of the western Pacific subtropical high, the convection "train effect" in Henan Province is also very obvious. This time, various small and medium-scale systems developed repeatedly in Funiu Mountain area and moved to Zhengzhou, forming a "train effect".

This repeated small and medium-scale system will increase the intensity of precipitation, and the precipitation will last for a long time, which is more likely to form local heavy rain.

The last condition is the favorable terrain provided by Funiu Mountain for this rainstorm, and the airflow climbs and rises, which is more likely to form convective instability.

Therefore, on the whole, the rainstorm in Zhengzhou is not determined by a single meteorological factor, but by the superposition of various favorable meteorological conditions.

Finally, I hope that the weather conditions of this rainstorm can move northward quickly, thus reducing the losses in Henan.