thermoclines are not the only force affecting droplets of water and dust in the atmosphere... electrostatic charges are definitely involved and why the most common form of lightning emanates from storm clouds
they are negatively charged
there are other types of lightning, like ball lightning and the Cosmic Thunderbolt (which is an extremely rare phenomenon), but storms, wind and lightning go together like peaches and cream... there is a connection between them all:
solar driving via electrons coming through the ionosphere when there is a moderate mass ejection nearby, the electrons are pushed down and clump the water and dust and create a cloud front and then wind and tada
i lived in australia, i'm used to intense storms... we have them also here at certain times in madeira and they coincided with some strong CMEs - i've been keeping an eye on that lately