This is most likely a result of the cloud formation rather than electro -
dynamical processes causing the clouds themselves (mind you, there are also clouds that produce that rain but do not produce lightning...).
«A study published in 2011 in Geophysical Research Letters on
causes of the 2010 Russian heat wave deduced that it «was due to internal atmospheric
dynamical processes» — Paging Al Gore: Peer - reviewed Study: «It is unlikely that the warming attributable to increasing greenhouse gas concentrations contributed significantly to the magnitude of the [Russian] heat wave»