Cirrus uncinus cloud
Cirrus uncinus is a species of cirrus cloud. The name cirrus uncinus is Latin for "curly hooks". Commonly called "mare's tail", this cloud species is very thin and generally sparse in the sky.
The clouds occur at high altitudes, at a temperature of about. They are generally seen when a warm or occluded front is approaching. They are very high in the troposphere and generally mean that precipitation, usually rain, is approaching.