The weather change process (wind speed, wind direction, air pressure, precipitation change) of a typhoon passing through a certain place.

In China, the areas where typhoons prevail are South China, Jianghuai and Jiangnan. The time is during the rainy season in North China in July and August. At this time, the middle and lower reaches of the Yangtze River are controlled by the subtropical high, and South China is affected by the southeast wind in the south of the subtropical high. When the typhoon transits:

Wind speed: If the weather is clear before crossing the border and the wind speed is low, the wind speed will increase when the cloud system around the typhoon invades. As the typhoon approaches, the wind speed will increase, and the closer to the center, the greater the wind speed.

Wind direction: Before the typhoon crosses the border, if there is no strong convective weather, it is often southerly. After the typhoon hit, the wind direction changed to southeast wind or east wind, bringing a lot of water vapor, increasing the cloud cover and gradually lowering the cloud base.

Air pressure: If the weather is fine and the air pressure is high before crossing the border, especially in the area controlled by subtropical high, the air pressure will start to decrease when the typhoon crosses the border. Because the typhoon is a cyclone weather system, the closer it is to the center, the greater the pressure. If a place is lucky enough to enter the eye of the typhoon, the air pressure will increase.

Precipitation: The precipitation in the cloud system near the typhoon is a long-term convective precipitation. When the typhoon crosses the border, there will be continuous heavy rain in the local area. Rainfall is related to the intensity and center distance of the typhoon, which can often last until the typhoon moves out or dissipates.