Evening Cirrus

Cirrus clouds represent the large group of high clouds (CHx). Because they are so high, they often catch the sun's light well after the sun has fallen below the horizon, offering beautiful contrasts of reds, oranges and yellows against a dark blue evening sky. Tonight, I found a large amount of CH2 clouds (Cirrus Floccus) and CH4 clouds (Cirrus Fibratus).

Cirrus Floccus is categorized as CH2, which also includes Cirrus Spissatus and Cirrus Castellanus. Cirrus Floccus is defined as cirrus in cumuliform tufts. Spissatus is typically smoothed fan-like cirrus that is progressively dense. Castellanus often have associated virga with small turrets.

The picture below shows Cirrus Floccus for the most part.

Cirrus Fibratus (CH4) is described as cirrus with filaments and is often arranged in parallel lines, as seen below.

Cirrus Floccus

Cirrus Floccus and Fibratus

Cirrus Floccus should be distinguished from Cirrocumulus Floccus (CH9) which are much higher, rarer and form at low temperatures.