How is thunder formed in a thunderstorm?

Answer 1

Three basic ingredients are required for a thunderstorm to form: moisture, rising/unstable air, and a lifting mechanism to force this rising air higher and faster.

Insolation is one such mechanism caused by the sun heating the surface of the earth, adding lift (thermals) to already rising, unstable air. Another mechanism would be where hills, mountains, or even multi-directional winds provide a point of convergence where different air masses, carrying various amounts of heat and moisture, can meet and form an uprising of unstable air.

However the uprising is driven, it will continue rising as long as it remains warmer than the air around it. As the air rises (convects), it transfers some heat energy to the higher levels of the atmosphere. The water vapor in the rising air begins to cool also, condensing into a cloud, and releasing more heat energy. This release of heat energy helps drive the upward movement of the unstable air, creating a low pressure area under the storm system, while cloud formation continues at ever higher levels.

The cloud eventually grows upward to altitudes where the temperature is below freezing. The water vapor condenses as water droplets which eventually freeze. Both carry static electrical charges. Ice particles usually have positive charges, and rain droplets usually have negative charges. When the static charges build up enough, a discharge occurs in what we call a lightning bolt. The discharge generates a momentary void in the air, that is very rapidly filled by the displaced air moving back in to fill the void. This is what generates the sound wave we call thunder.

There are three stages to a thunderstorm: the cumulus stage, the mature stage, and the dissipation stage. When a thunderstorm begins to form, it does so at the cumulus stage. From there, it advances in activity until it reaches its peak at the mature stage. Then, entering the dissipation stage, begins to gradually lose (dissipate) more energy than it generates.

The most common cause of thunder storm formation is a cold front, a cold front is a fast moving air mass of cold, dense, dry air. When this cold front comes into contact with warmer and more humid air, it will slide, like a wedge, under the warmer and less dense air, forcing it to rise. This cold front provides a steep slope causing the warmer air to move up more quickly. As it rises, it will expand and cool. Since the air is cooling, the concentration of water vapor approaches its saturation point. Once saturation is reached, a cloud starts to form. Since the warm air was forced upward so abruptly, a strong upward development of cloud growth can be observed (cumulus stage). The cloud that you see, is a cumulus cloud, changing into cumulonimbus as it gains altitude. If the upwelling is strong enough the cumulonimbus cloud can reach the bottom of the troposphere and start spreading outward (capping), forming the signature anvil structure (cumulonimbus indus), the characteristic thunderhead,marking the mature stage. At the end of this stage the droplets come together and begin to fall as rain or hail. Precipitation marks the beginning of the dissipation stage where the energy dissipates faster than it can accumulate. The energy dissipates into the surrounding air causing the storm to lose its intensity and finally to disappear.

This is a common scenario of how a thunder storm forms and ends. Storms can be formed by radical changes in weather systems or just because the clouds reach their saturation points.

Answer 2

A thunderstorm occurs when moist air near the ground becomes heated and rises, creating cumulonimbus clouds which produces precipitation. Lightning is created from electrical charges accumulating at the base of the clouds. As a result of being heated, air in the path of the lightning expands, creating thunder

Answer 3

thunder and lightning are both virtually the same lightining is what we see of an effect and thunder is what we hear of the same effect. There is still debate about the initial build up of lightning but ice is guessed to be a factor (assuming you are reffering to regular lightning in a thunderstorm). It is hypothesized that ice causes a disruption and causes the electrons (-) and protons (+) to separate causing an extreme electrical charge.