Typhoon will bring all kinds of heavy rainfall, but why is it dry and sultry before it comes?

The weather before the typhoon was particularly hot and dry, which may be caused by many reasons. The possible reasons are:

1, which is mainly related to the cause of typhoon formation. The continuous high-temperature exposure of the sun leads to the evaporation of water on the ocean surface, which will gradually repel other gas components in the air and make the humidity of the air increase sharply. This high humidity air is the basis of typhoon formation. Once this foundation is established, when there are external conditions to promote the condensation of water vapor in high humidity air, the pressure of air will drop sharply, resulting in atmospheric negative pressure relative to other surrounding air, which is the central negative pressure of typhoon.

2. Typhoon is a low-pressure system. According to the typhoon structure diagram, the airflow in the typhoon low-pressure center is rising, and the ascending airflow will flow around at high altitude and sink at the outer edge of the typhoon, so the area at the outer edge of the typhoon will be sultry because of downward flow. The peripheral air flow is downward, which is very stuffy and dreary, so when the typhoon comes, the air feels extremely dry and sultry.

3. In addition, there are the influences of latitude and topography. Typhoons generally occur in Taiwan Province, Fujian, Guangdong, Hainan, Zhejiang and Guangxi in China. These areas are located in subtropical areas with low latitudes, and latitude waters provide abundant heat and water vapor for typhoons. In addition, the Pacific Ocean has the widest area in the tropics, with more heat and water vapor.

4. According to the consulted data, it can be seen that the formation of wind is related to the pressure difference. The wind blows from a place with relatively low temperature and high pressure to a place with high temperature and low pressure. Of course, typhoons also blow from places with relatively low temperature and high pressure to places with high temperature and low pressure, so it was dry and sultry before the typhoon came.