Thunderstorms are formed because of intense convection on moist hot days. Convection refers to the transfer of heat through the movement of fluids, such as air or water. Thunderstorms are a type of weather phenomenon that involves the rapid upward movement of warm, moist air, which eventually leads to the formation of towering cumulonimbus clouds.

Here is a detailed explanation of why thunderstorms form due to intense convection on moist hot days:

1. Introduction to Thunderstorms:
- Thunderstorms are characterized by the presence of cumulonimbus clouds, which are large, dense, and vertically towering.
- These clouds are formed due to the rapid upward movement of warm, moist air.

2. Intense Convection:
- Thunderstorms are primarily formed due to intense convection, which occurs when there is a significant temperature difference between the surface and the upper atmosphere.
- On a hot and moist day, the surface temperature rises, leading to the heating of the lower layers of the atmosphere.
- This heating causes the air near the surface to become warmer and less dense, making it rise rapidly.

3. Updrafts and Downdrafts:
- As the warm air rises, it forms updrafts, which are powerful currents of air moving upward.
- These updrafts carry moisture and heat energy with them as they ascend.
- As the air rises higher into the atmosphere, it cools and condenses, forming cumulonimbus clouds.
- Within these clouds, the rising air cools further, and water droplets and ice crystals start to form, leading to the development of precipitation.

4. Thunderstorm Characteristics:
- Thunderstorms are often associated with heavy rainfall, lightning, strong winds, and sometimes hail.
- The rapid movement of air within the storm system creates strong updrafts and downdrafts, contributing to the formation of severe weather conditions.

5. Moisture Source:
- Moisture is a crucial ingredient for thunderstorm formation.
- On hot days, there is often an abundant supply of moisture available in the lower layers of the atmosphere, which can be provided by sources such as bodies of water, evaporation, or advection from other regions.

In conclusion, thunderstorms are formed due to intense convection on hot and moist days. The rapid upward movement of warm, moist air creates powerful updrafts within cumulonimbus clouds, leading to the formation of thunderstorms. These storms are characterized by heavy rainfall, lightning, and strong winds.