The flat top indicates that the cloud is thickening and potentially forming into a thunderstorm. These clouds are also known as tower clouds due to their distinctive, flat-topped appearance. What does a flat top cloud mean?Ī flat top cloud typically means that a cumulonimbus cloud is forming, which is a type of cloud that is responsible for thundershowers and other forms of precipitation.

This means that the base of the storm cloud is generally flatter and wider than the top, since the warm air is not able to reach the same altitudes as the cold air below it. When more moisture is added to the atmosphere, it is forced to stay in an area of stable air. This creates an area of warm air pushed up into the cold air above it, causing it to become more stable. Cold air is denser than warm air, so when a storm system moves in, cold air near the ground pushes warm air up into the atmosphere. Storm clouds are generally flat on the bottom because of the way air behaves at different temperatures.

A puffy white cloud with a flat bottom