Weather map representation of an occluded front

Credit: Windows to the Universe, Lisa Gardiner

At an occluded front, the cold air mass from a cold front meets the cool air ahead of a warm front. The warm air in between rises as these air masses come together. On a weather map the occluded front is shown as a purple line with alternating triangles and semicircles pointing in the direction that the front is moving. It ends at a low pressure area shown with a large ‘L’ on the map, and at the other end connects to cold and warm fronts.