How is the rainstorm in Zhengzhou formed?

Why is this rainstorm in Henan so strong? So long? I asked the director for everyone. There are three main reasons.

(1) Typhoon, come back! Although the distance of Typhoon Fireworks is 0/000 km from China/KLOC-,it has controlled the rainstorm in Henan province remotely. Under the guidance of "fireworks" and subtropical high, a large amount of water vapor is continuously transported from the sea to the land through the east wind, and it gathers into rain in Henan.

② Topographic reasons. After the easterly airflow meets Taihang Mountain and Funiu Mountain in Henan Province, it converges and rises in front of the mountain, resulting in concentrated rainfall range and strong rainfall.

③ The atmospheric circulation situation is stable, which leads to long rainfall duration. At present, only when the typhoon "Fireworks" is closer to China, the circulation situation will be adjusted, the source of water vapor will be cut off, and the rain in Henan will stop. (reprinted from the Central Meteorological Observatory)