wrote in message
...
To move a small volume with respect to its surroundings, you have to
apply energy to this 'localisated package' and not to its surroundings.

Yes but that's not a problem. Read up on how thermals are produced. A micro
burst isn't that different. It's a bit like a strong "anti thermal". ... The
sun warms up a large area then a small rain cloud cools part of it causing
that part to sink rapidly.... is one way to look at it. The ultimate source
of the energy is the sun just the same as for a thermal.