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.

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

They are seen as holes in a mid-level cloud deck with thin wisps under the hole. The thin cirrostratus clouds in the picture are made up of tiny supercooled water droplets.