What weather phenomenon occurs when warm, moist air moves over colder surfaces?

The phenomenon that occurs when warm, moist air moves over colder surfaces is known as advection fog. This type of fog forms when warm, moist air comes into contact with a surface that is significantly cooler, causing the air to cool and condense.

When the warm air is transported horizontally over the colder surface—such as a body of cold water or ground—its temperature drops, resulting in the condensation of water vapor in the air. This condensation leads to reduced visibility and the formation of fog. Advection fog is common in coastal areas and can occur when breezes move warm air over cooler ocean waters.

This process is crucial to understand as it directly relates to how temperature differentials can result in unique weather phenomena that affect visibility and safety for both aviation and road travel.