Lightning or thunder is a natural phenomenon that typically appears during the rainy season where the sky appeared a flash of light momentarily blinding flash is usually called a few moments later followed with a booming voice called Thunder. This emergence of the time difference caused by difference between the speed of sound and the speed of light.
Lightning is a natural phenomenon that we can analogikan with a giant capacitor, whereby the first plate is the cloud (negative plate or plates can be positive) and second plates of the earth (considered neutral). As you already know the capacitor is a passive component in the electrical circuit that can store energy for a moment (energy storage). Lightning also can occur from cloud to cloud (intercloud), where one of the negatively charged cloud and another cloud of positively charged.
Lightning occurs because there is a potential difference between cloud and earth or with other clouds. The process of charge on a cloud because he was constantly engaged on a regular basis, and during the movement he will interact with other clouds are gathering so that the negative charge on one side (up or down), while positive charges gather on the reverse side. If the potential difference between clouds and the earth is big enough, then there will be disposal of negative charge (electrons) from the cloud to earth or vice versa to achieve equilibrium.
In the process of this charge, the media through which the electron is in the air. At the time of the electrons can penetrate these air isolation threshold there was an explosion sound. Thunderstorms are more common in the rainy season, because in these circumstances the air contains a higher moisture content so that the insulating power down and flows more easily flowing. Because there are clouds of negatively charged and positively charged clouds, the lightning can also occur between clouds of different loads.