How daytime fog forms

Published: Jan. 31, 2023 at 2:06 PM CST
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MOBILE, Ala. (WALA) - If you are a regular bayway or causeway commuter you know that fog can impact your drive in the morning, in the middle of the day, and even in the afternoon. Why is that?

It’s called advection fog.

Radiation Fog

Around our area there are two main types of fog. Radiation fog is the most common. That’s the type you generally see in the mornings. All it takes is clear skies and calm winds. As the air temperatures drop, moisture condensates near the surface and fog forms.

This kind of fog generally will generally burn off as the day warms up and goes along.

Advection Fog

Advection fog is formed in a different way when warm air moves over cold water. The warm air will then cool off, moisture will condensate, and fog will form.

This type of fog can hang around all day as long as there is cooler water below and warmer air above. This will only last over water bodies, so once you get a mile or two away from the water the fog goes away.

Right over the water is where advection fog forms. It can happen right during the middle of the day and create traffic troubles all day long.


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