What is advection fog?
Quick Answer
Advection fog forms when warm, moist air moves over a cooler surface and cools to its dew point. It is common near coasts and can be thick enough to reduce visibility sharply.
The Full Story
Unlike radiation fog, which usually forms on calm nights as the ground cools, advection fog develops when air itself is carried horizontally over a cold surface. This often happens when moist air from the sea moves over colder land or water, or when warm air passes over a cold ocean current. The cooling causes water vapour to condense into tiny droplets suspended in the air. Famous examples include fog along the California coast, where ocean currents and marine air often combine to create long-lasting fog banks.
Key Facts
YouTube Angle
Suggested video title for this topic:
"The fog that moves in, not the fog that falls!"