Thunderstorms, by their very nature, are rain showers containing lightning and thunder. Thunderstorms are fairly complex beasts of nature. In order to develop, a thunderstorm needs moisture, instability, and a lifting or trigger mechanism.

During the initial stage, a developing thunderstorm begins as a cumulus cloud with upward air motion (the updraft) throughout most of the cloud. This is called the CUMULUS STAGE. If the air temperature in this cloud is warmer or more buoyant than the surrounding atmosphere, it can continue to rise, produce precipitation, and grow into a thunderstorm.

A thunderstorm reaches its MATURE STAGE when the rising air develops a counterpart: sinking, rain-cooled air. This is known as the downdraft. This is usually when the thunderstorm is strongest and has the highest potential to produce severe weather. When the downdraft begins to dominate the thunderstorm, it has reached its DISSIPATING STAGE.

A thunderstorm needs a supply of fuel (relatively warm and moist air) to survive. When the cool downdraft begins to spread out and cut off this fuel supply, the thunderstorm lose strength and dissipate. It should be noted that severe weather can still occur in the dissipating stage. The life cycle for an individual thunderstorm cell is about 30 minutes. During its life cycle, the two main components of a thunderstorm are the updraft and downdraft.

(Cumulus stage photo – Steve Tegtmeirer - NSSL) (Center photo – )
(Dissipating stage photo – NOAA)
(Diagram adapted from C. A. Doswell III, 1985: The Operational Meteorology of Convective Weather. NOAA Tech Memo ERL ESG-15.)