What is the predominant factor for the formation of steam fog?

The predominant factor for the formation of steam fog is cold dry air. Steam fog forms when cold air moves over warmer water, leading to the evaporation of water into the colder air above. This results in the warm water vapor rising into the colder atmosphere where it cools rapidly, causing condensation into tiny water droplets, creating the fog. The key element here is the temperature differential, where the cold air contributes to the condensation process, forming fog as the warm, moist air rises and cools.

In this case, warm air alone is not sufficient to create steam fog, as it requires the presence of cold air to cool the evaporated water vapor. Similarly, stable conditions typically indicate a lack of vertical motion in the atmosphere, which might prevent the mixing necessary for fog formation. While high pressure systems can lead to stable and clear weather, they do not directly influence the creation of steam fog in the same way cold dry air interacting with warm water does.