FAA Ground School Practice Test

Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?

1. Cloud formation

2. Precipitation beginning to fall

3. Lightning activity

4. Rapid temperature drop

The correct answer is: Precipitation beginning to fall

The beginning of the mature stage of a thunderstorm is indicated by precipitation beginning to fall. During this stage, the thunderstorm reaches its most intense development. As the updrafts within the storm continue to grow, they support the formation of large raindrops. Once these droplets become heavy enough to overcome the upward airflow, they start to fall as precipitation. This falling rain marks a defining transition where the storm is actively releasing energy and moisture into the atmosphere, often leading to heavier rainfall, hail, and the potential for severe weather. While cloud formation is a precursor to the storm and helps initiate the process, it does not specifically indicate the mature stage. Lightning activity does occur in the mature stage, but it is a result of updrafts and downdrafts interacting rather than a signal that the stage has begun. A rapid temperature drop may happen as precipitation begins to cool the environment, but it is not the primary signal for the onset of the mature stage. Thus, the commencement of precipitation is the most accurate indicator of this critical phase in the life cycle of a thunderstorm.