qVertical wind
shear creates a horizontal vortex.
qThe vortex is
tilted vertically by strong updrafts and forms a mesocyclone.
qThe vortex
stretches downward when the mesocyclone intensified.
qA wall cloud
is formed under the cloud base, which then develops into a tornadoes.
qOnly about
1/2 of all mesocyclones actually spawn a tornado
q