Refer to figure.
A typical airmass thunderstorm develops in three distinct stages: the cumulus (initial) stage, the mature stage, and the dissipating stage.

Cumulus (Initial) Stage:
This stage is dominated by continuous upward air currents (updrafts). The lifting mechanism begins the vertical movement of air, causing the development of cumulus clouds. These updrafts can be extremely strong, sometimes reaching speeds of 3000 feet per minute. At this point, precipitation hasn’t started, because water droplets and ice crystals are repeatedly lifted and fall within the cloud, gaining size with each cycle. This stage typically lasts about 15 minutes, after which the storm progresses to the next phase.

Mature stage:
This is the most intense phase of the thunderstorm and begins when precipitation starts to reach the ground. The weight of water droplets eventually overcomes the strength of the updrafts, causing downdrafts to form. As the rain falls, it drags air with it, which descends rapidly and spreads out along the ground. This produces a sudden drop in temperature, an increase in surface pressure, gusty winds, and turbulent conditions.

The most severe turbulence occurs where rising and falling air currents meet, especially below the cloud base. In some cases, a roll cloud, a horizontal, tube-shaped cloud, forms near the lower front edge of the storm due to intense wind shear. The mature stage can last up to 30 minutes.

Dissipating stage:
The storm enters its final stage once downdrafts dominate the internal air movement. As falling precipitation disturbs more air aloft, the updrafts weaken and are eventually replaced entirely by descending air. During this phase, upper-level winds often carry the top of the cloud downwind, forming the classic anvil-shaped cloud top. With the energy supply cut off, the storm rapidly weakens and dissipates.