How are tornadoes formed?
A tornado is a vortex and a violent whirlpool in the air. Air around the tornado's axis rotates rapidly, attracted by the extreme decrease in pressure at the center of the tornado. Within a thin layer of air near the ground, the wind is sucked into the vortex from all directions. It then becomes a vortex that rotates upward around the axis, and the wind in the tornado is always cyclonic, with the pressure at its center being as low as 10% lower than the surrounding pressure.

The formation of a tornado
Tornadoes are the products of thunderstorms in clouds. They are formed in strong thunderstorms, with a significant temperature difference between the ground and the cloud base: the ground temperature is in the range of 20-25 degrees Celsius, while the temperature at the base of the thunderstorm cloud drops to the teens, and at 4,000 meters above sea level, it drops to 0 degrees Celsius. At 8,000 meters, the temperature drops to -30 degrees Celsius. This rapid descent of cold air and the violent ascent of hot air create many small vortices. Before these small vortices can develop, they often rise to the cloud base in groups of three or five, sometimes stretching and contracting as they rotate and roll. It's only when the up-and-down agitation is very strong that large vortices—tornadoes—are formed. Tornadoes typically occur in summer and often arrive together with strong thunderstorm clouds.
Specifically, a tornado is a form of energy release within a small area that represents a small part of the enormous energy within a thunderstorm. The formation of a tornado can be divided into four stages:
（1）The instability of the atmosphere produces strong upward air currents, which are further strengthened by the influence of the large transverse air currents within the jet stream.

(2) Due to the interaction with the wind that has shear in both speed and direction in the vertical direction, rising air currents begin to rotate in the middle of the troposphere, forming mesoscale cyclones.

As a mesoscale cyclone develops toward the ground and extends upward, it itself becomes thinner and stronger. At the same time, a small-area enhancement of coalescence occurs, which is the initial formation of a tornado within the cyclone. This produces the same process as for a cyclone, forming the tornado core.

The rotation in the core of a tornado is different from that in a cyclone. Its intensity is sufficient to extend the tornado all the way to the ground. When the developing vortex reaches the height of the ground, the atmospheric pressure at the ground suddenly drops, and the wind speed at the ground suddenly increases, forming a tornado.