What forms a thunder storm?

Answer 1

Thunderstorms form when an air mass becomes so unstable that it overturns (convects) violently. "Unstable" means that the air in the lowest layers is unusually warm and humid, or that the upper layers are unusually cool, or oftentimes, both. Rising near-surface air in an unstable air mass expands and cools, and finds itself still warmer than it's environment, which causes it to rise even farther. If enough water vapor is present, some of this vapor condenses into a cloud, releasing heat, which makes the air parcel even warmer, forcing it to rise yet again. In thunderstorms, this process continues to feed on water vapor in the lower atmosphere, pumping air warmed by condensation as high as 40,000 to 60,000 feet (8 to 12 miles). Thunderstorms are more common in the afternoon over land, when daytime heating of the land by the sun causes the lower part of the troposphere to become unstable. Or, some thunderstorms can form from the upper atmosphere becoming unusually cool, due to the approach of an upper air disturbance. In this case storms can form at any time of day, even when there hasn't been daytime heating of the land. One absolute requirement, however, is there has to be sufficient water vapor to feed the storm. This is the fuel for the thunderstorm. As the storm uses up this fuel, it is converted to rainfall. Eventually, the storm stabilizes the atmosphere, through using up the excess water vapor, cooling the lower troposphere, and warming the upper troposphere. A discussion of what causes lightning can be found here.Interesting facts:NATURE'S AWESOME POWER It is estimated that there are around 44,000 thunderstorms that occur around the Earth every day. The average thunderstorm releases the energy equivalent of a 20 kiloton nuclear weapon, or a small nuclear power plant.

Answer 2

A thunderstorm forms when warm, moist air rises rapidly into colder air in the atmosphere, creating instability. This causes the air to cool and condense, forming cumulonimbus clouds. The rapid upward and downward movement of air within these clouds results in the development of lightning, thunder, heavy rain, and sometimes hail.