Texture V

cirrocumulus-clouds

Cirrocumulus patch in the northwest sky at dusk • 22 October 2017 • Mississauga, Ontario

Continuing a series of monthly posts exploring texture in photographs.

From cirro (‘curl of hair’) and cumulus (‘heaped’), these high-altitude cirrocumulus clouds contain ice crystals and supercooled liquid water droplets. Small individual cloudlets usually form larger patches that spread across the sky, as seen here. This short-lived and somewhat rare type of formation is commonly referred to as “herringbone” or “mackerel sky”.

Large cirrocumulus patches form ahead of low-pressure systems, indicating that weather conditions are deteriorating and rain is eight to ten hours away. The rain will be brief, however, because it moves away quickly along with the warm front. If seen after rain, cirrocumulus clouds mean that the weather is improving.

This phenomenon and the old practice of forecasting weather from nature are reflected in a couple of rhymes:

Mackerel scales and mare’s tails
Make tall ships carry low sails

and

Mackerel sky,
mackerel sky,
Never long wet,
never long dry.