Occluded front

A warm front is shown as semi-circles in a traditional weather map, also pointing to its direction of travel.

An occluded front is a combination of those two signs: they are indicated on a weather map either by a purple line with alternating semicircles and triangles pointing to the direction of travel, or by red semicircles and blue triangles pointing to the direction of travel.

A wide variety of weather can be found along an occluded front, with heavy thunderstorms and tornadoes possible, but usually, their passage is instead associated with a drying of the air mass.

Small isolated occluded fronts often remain for a period after a low-pressure system has decayed and disappeared and these create cloudy conditions with patchy areas of rain or showers.

However, the clouds and precipitation are not really the location where the projection on the Earth's surface of the occluded front is, but it is with the TROWAL position.