"Rodney Blackall" wrote
...
In article , Szczepan Bia³ek
wrote:
Away from the ground, vertical air currents will be overwhelmingly more
important than the static field. If the field is really large, as in a
thunderstorm, then the vertical currents will be very strong and
largely the cause of the charging.

May be that "vertical air currents" are the electric winds in its nature.
S*

No. It is easy to predict when these strong upcurrents can occur in the
mid-troposphere from the degree of instability in the atmosphere. When
they
can be large the weather forecast will include thunder.

The electrification of clouds is a complex topic of continuing research, I
suggest you "google" the subject.

I did that already. Everybody are continuing research in situation where all
is simple. Droplets which hang in the air are charged (like in the
Millican's experiment). The excess of electrons are in continual
circulation. In sunny days they migrate up attached to water vapour and next
fall down as current and lightning. When droplets loss the charge they fall
down.
S*