What occurs when an air mass passes over a warm surface?

When an air mass passes over a warm surface, it causes the air close to the surface to warm up as well. This warming results in the air becoming less dense and rising, which is a fundamental principle of convection. As the warm air rises, it can lead to the formation of convective currents. These currents can create updrafts in the atmosphere, contributing to various weather phenomena, including cloud formation and possibly precipitation if the conditions are right.

In contrast, stable air tends to occur when air is cooler and more uniform, preventing significant vertical movement. Thunderstorms generally require more specific conditions, including moisture and unstable air, to develop; they are not a direct consequence of simply passing over a warm surface. Fog dissipates when the air warms up and the moisture in it can no longer remain suspended, but this is not directly linked to the general pattern of air interaction with a warm surface. Thus, the emergence of convective currents due to the warming of air is the primary event occurring in this scenario.