What's a Warm Occlusion Weather Front?

A warm air occlusion or occluded front is less common than a cold occlusion. A warm occlusion occurs as cool air moves rapidly into an area with an existing warm front. The difference from a cold occlusion is that the approaching cool air is not as cold as the retreating cold air in the existing front. In other words, the fast-moving, incoming air is cold, but not as cold as the air mass ahead of it. Precipitation can usually be expected when an occluded front passes through an area.

What's an Occluded Front?

Sometimes a cold front will "catch up" to a warm front and overtake both it and the cooler air out ahead of it. If this happens, an occluded front is born. Occluded fronts get their name from the fact that when the cold air pushes underneath the warm air, it lifts the warm air up from the ground, which makes it hidden, or "occluded." 

Occluded fronts usually form with mature low-pressure areas. They act like both warm and cold fronts.

The symbol for an occluded front is a purple line with alternating triangles and semi-circles (also purple) pointing in the direction the front is moving.

Sometimes a cold front will "catch up" to a warm front and overtake both it and the cooler air out ahead of it. If this happens, an occluded front is born. Occluded fronts get their name from the fact that when the cold air pushes underneath the warm air, it lifts the warm air up from the ground, which makes it hidden, or "occluded." 

Updated by Tiffany Means