How are tornados born?

Answer 1

Tornado development (called tornadogenesis) begins when differences in wind speed and/or direction at different altitudes, called vertical wind shear, creates horizontal vortices of air. These vortices can then be turned vertical by a thunderstorm updraft, which takes on this rotation to become a mesocyclone. Under the right conditions a downdraft can descend from th back of the storm and wrap around the mesocyclone, tightening and intensifying it. This smaller, stronger circulation is the tornado.

Answer 2

Tornadoes are born from severe thunderstorms that have strong, rotating updrafts. When certain atmospheric conditions are present, the rotation can intensify and extend downward, forming a funnel cloud. If the funnel cloud reaches the ground, it becomes a tornado.