What feature is typically associated with the cumulus stage of a thunderstorm?

The cumulus stage of a thunderstorm is characterized by the presence of a continuous updraft. During this initial stage, warm, moist air rises and cools as it ascends, which leads to cloud formation. The updrafts are essential for the development of the cumulus clouds, as they are what allows the cloud to grow vertically. This stage does not yet involve significant downdrafts or precipitation; rather, the conditions are focused on the continuous supply of warm air rising, which fosters the development of the cloud structure associated with thunderstorms.

Other options describe phenomena that occur in later stages of thunderstorm development, such as the presence of downdrafts or precipitation, which typically emerge when the storm reaches maturity. For instance, rain beginning at the surface signifies transitioning to the mature stage of the storm, where both updrafts and downdrafts coexist. Likewise, features like roll clouds are associated with the outflow boundaries or gust fronts that occur later in a thunderstorm's life cycle. Thus, recognizing the defining characteristics of the cumulus stage helps to understand the broader lifecycle of thunderstorms.