Thursday, December 18, 2014

Occluded Front

We've learned that a cold front is a bunch of cold air moving along, and a warm front is a bunch of warm air moving along.

What if a really fast cold front catches up to a slower moving warm front?

Or a really fast warm front catches up to a slower moving cold front?

When either of those things happen, it is called an occluded front.
The word occluded means to close or shut.

Remember that the cold air is heavier than warm air, so whenever a cold front catches up to a warm front, it pushes under the warm front and the warm air goes up.
When the warm air catches up to a cold front, it goes up above the cold air.

Sometimes storms and even funnel clouds that could turn into tornadoes happen at occluded fronts, because the cold and hot air is all getting pushed around in different locations.

We know the picture for the cold front is blue triangles, and the picture for the warm front is half red circles.
The picture for the occluded front is purple triangles and half circles on the same line.

(from: wikipedia - occluded front)

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