(1.) Why do you think non-severe thunderstorms have such a short lifetime (~1/2 hour)?
(A.) Raindrops which are produced eventually drag air downward shutting off the updraft.
(B.) Raindrops can't stay up longer than 1/2 hour.
(C.) After 1/2 hour cloud shadows can't inhibit updrafts.
(2.) What parts of a non-severe thunderstorm could be changed in order that the system be transformed into a severe thunderstorm?
(A.) Arrange the downdrafts so they do not fall back into the updrafts. (B.) Eliminate the anvil to reduce shadows at the ground.
(C.) Seed the cloud to produce more, but smaller raindrops. (3.) What atmosphere conditions would you add to extend the lifetime of these storms?
(A.) Larger raindrops therefore strengthening the downdraft.
(B.) More moisture in the atmosphere.
(C.) Wind speeds which increase with height.
Descending
Motion