A streaky cloud, often referring to a feature observed in cirrus clouds, is characterized by hair-like filaments called fall streaks composed of heavier ice crystals falling from the cloud. These are similar to virga seen in liquid-water clouds.
Understanding Fall Streaks
Fall streaks are a key characteristic of what might be described as a "streaky cloud," particularly within cirrus formations.
- Composition: Made of heavier ice crystals.
- Formation: These crystals descend from the cirrus cloud.
- Similarity to Virga: Analogous to virga, which is precipitation that evaporates before reaching the ground in liquid-water clouds.
- Influence of Wind Shear: The sizes and shapes of these fall streaks are influenced by the wind shear.
Diurnal Variation of Cirrus Clouds
Cirrus cloud cover and, consequently, the appearance of streaky formations due to fall streaks can vary throughout the day, referred to as diurnal variation. This means the presence and appearance of these clouds can change over the course of a day.
