The type of front that involves three different air masses is an occluded front.

What an occluded front is

An occluded front forms when a faster-moving cold front catches up to a slower-moving warm front in a low-pressure system.

This process brings together three air masses: very cold air, cool air, and warm air that gets lifted up above the colder air near the surface.

Key features of an occluded front

  • It involves three air masses: cold, cool, and warm.
  • The warm air is forced aloft as the colder air wedges underneath it.
  • Weather along an occluded front often includes widespread clouds, steady rain, and sometimes thunderstorms, followed by cooler, more stable conditions.

Quick mental picture

Imagine a racing situation in the atmosphere:

  • A cold front (very cold air) is moving quickly and catches a warm front (warm air ahead of cooler air).
  • When they meet, the warm air gets squeezed and lifted above, leaving two cooler air masses at the surface and the warm one up high; that “stacked” setup is the occluded front.

So whenever a question asks “what kind of front involves 3 different air masses,” the answer is: an occluded front.

Information gathered from public forums or data available on the internet and portrayed here.