WeatherSharon's Weather Blog


How lightning forms

Lightning is a form of electricity
Posted at 4:24 PM, Apr 27, 2022

CORPUS CHRISTI, Texas — Thunderstorms moved through south Texas Monday night and gave Corpus Christi a nice light show as lightning lit up the evening sky.

Basically, lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground as opposite electrical charges build.

Thunderstorms are very turbulent environments with updrafts and downdrafts which carry water droplets and ice crystals through the cloud. This causes a separation of charges in the cloud with a negative charge at the bottom of the cloud and positive at the top.

As positive and negative charges begin to separate within the cloud, an electric field is generated between its top and base. Further separation of these charges into pools of positive and negative regions results in a strengthening of the electric field.

In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalizes the charged regions in the atmosphere until the opposite charges build up again.

The electric field within the storm is not the only one that develops. Below the negatively charged storm base, positive charge begins to pool within the surface of the earth.

This positive charge will shadow the storm wherever it goes, and is responsible for cloud-to-ground lightning. However, the electric field within the storm is much stronger than the one between the storm base and the earth's surface, so most lightning occurs within the storm cloud itself.

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