High altitude, wispy streaks consisting of ice crystals.

Shafts of light radiating from the position of the sun.

Well defined heaps of puffy clouds found at all elevations, exhibiting a range of species and varieties.

Any of several atmospheric optical phenomena in which the sun appears to have risen, but is actually still some distance below the horizon.

Clouds caused by human activity.

Steam rising from the Potomac.

Horizontally layered clouds with little vertical development.

The reflection of the sun on tiny ice crystals in the sky, forming a vertical column.

Temporary dark spots on the suns surface caused by concentrations of magnetic flux that inhibit convection. Under the right conditions they can be viewed with the naked eye.

Clouds transparent enough to reveal the position of the sun.

Wavy, undulating cloud formations found in both stratiform and cumuliform cloud types.

Streaks of precipitation that evaporate before reaching the ground.

Smoke that drifted east from forest fires in several western states and Canada.