Warm moist air rises, causing upward vertical motion of air into the thunderstorm.
The air diverges, or spreads out, above the storm.
Cold air from about 20,000 feet sinks into the thunderstorm, giving the storm downward vertical motion
The cold air and the warm air collide in the thunderstorm, and this creates a vortex, or a spinning, in the thunderstorm
This spinning leads a sinking cloud to form what is called a wall cloud.
The spinning and sinking intensify, allowing the cloud to get closer to the ground. This is known as the funnel cloud.
Now the spinning and sinking leads to extreme downward motion. The cloud touches the ground, and when it does it is known as a tornado
Step-by-step explanation: