Today, 10 basic cloud forms are recognized, all of which owe a debt to Howard's nomenclature. Some are low-level clouds that exist below 6,500 feet, such as cumulus, stratus, and stratocumulus.

The thin cirrostratus clouds in the picture are made up of tiny supercooled water droplets. This means the water remains a liquid but the temperature is below freezing. Image courtesy of Laura Goodman ...

Cirrostratus clouds drifting over Metro Atlanta produced my favorite atmospheric optical phenomena: A sun halo, with both sundogs on each side of the sun.