Szczepan Bialek schrieb:
Anyway cloud must discharge the voltage before fall down as rain.

Really? One can regularly observe rain, both convective or stratiform,
falling down without any previous lightning.
Anyway, since cloud and ground are oppositely charged (otherwise you
would not get discharges in the form of C-G lightning), the
electrostatic force would *attract* cloud droplets towards the ground,
so they would fall faster *before* the discharge. However, this force is
several orders of magnitude weaker than the force exercised by
gravitation and air currents.

Falk