fleecy cloudlet

Small, rounded white clouds with a cotton-like appearance are often called 'sheep', as their presence in the sky reminds us of a flock of them. Their diminutive form is the most widespread. It is the name given in popular meteorology to the elements or units that form altocumulus clouds of the species floccus. Their appearance often anticipates a change in the weather, as they frequently precede the arrival of a frontal system that brings rain ('Fleecy clouds in the sky, puddles on the ground').