Thunderstorms generate lighting within 20 minutes because the mechanism to separate charge. The dipolar sturcture of water and electrification that happens when freezing water. Thermoelectric effect allows positively ionized molecules of the water partical to travel from warm to cool temeratures. The begins the preliminary breakdown to the stepped leader.
There is a few times of lightning that exist. There is the cloud-to-cloud, cloud to ground, and cloud to air. The one that is well known and feared is the cloud to ground lightning strikes. This is caused from a discharge inside a thundercloud. It starts out as a faint negative charged channel that emerges from the base of the thundercloud. From the influence of the electric field established between the cloud and the ground it creates a stepped leader that shoots towards the ground in s series of luminous steps of about 1 microsecond and 50-100 meters in length with a pause of about 50 microseconds. When the stepped leader channel reaches the ground there is about 5 Coulombs of negative charge on it and has a very strong electric potential. The ground usually have a electric potential of about -10x10*8 volts. The leader reaches the ground about 50-100 meters above the surface and this is when the discharge process starts and is calle the return stoke. At the point of the meeting of the lightning channel lead and the ground there is a elecric and magnetic field charge generated. The field changes have rapid variations along the channel of the stepped leader and the field also have electrostatic, inductive and radiative components, which all these components have different frequencies. Therefore, the shape of the field change have a strong influence of the radial distance from the channel.
Once the current in the stepped leader channel has ceased to flow, there is a pause of about 20-50 milliseconds that may have another leader come out and strike roughly the same area as the already established but faint lightning channel. However, this leader is not stepped but is continuous and called a dart leader. Dart leaders have a similiar process as the stepped channel leader but carry one coulomb of charge and initiate return. The air that is between the cloud and ground channel is ionized because the intense heat and breaks the oxygen molecules into ionic components. This causes multiple stokes of lightning in fractions of a second to give the apperance of flickering.
Most active thunderclouds is in cumulus congestus (a cloud formation). This is when the upper part of the cloud forms of an anvil.
