Cirrus floccus
Ci flo
Cirrus floccus
© Wetterkurs.ch
Description
The name "floccus" (Latin: flake, tuft) describes the characteristic appearance of this cirrus species, which occurs in the form of small, rounded tufts or flakes. Cirrus floccus consists of small, cumuliform cloud puffs with a slightly frayed base, often accompanied by fall streaks (virga). These clouds form at high altitudes, where local instabilities in thin air layers lead to convective updrafts. The individual tufts often appear irregularly distributed across the sky and can dissolve rapidly or transition into other cirrus forms. Cirrus floccus is a rather rare sight and is sometimes confused with cirrocumulus, but is larger and less regularly arranged.
Identification Features
- Small, rounded or tuft-shaped cloud elements at high altitude
- Individual tufts appear slightly cumuliform and have some vertical extent
- Often accompanied by fall streaks (virga) hanging beneath the tufts
- The base of the tufts often appears frayed or ragged
- Larger than cirrocumulus elements and less regularly arranged
- Pure white and translucent, composed of ice crystals
- Irregular distribution across the sky, no widespread coverage
- Individual elements can change and dissolve rapidly
Occurrence by genus
Highlighted: all genera with which floccus occurs.
Meteorological Significance
Cirrus floccus indicates local instability in the upper troposphere, suggesting moisture advection and turbulence at high altitudes. When this cloud form appears more frequently, it can be an early sign of an approaching warm front or an approaching low-pressure system. In combination with increasing cloud thickening — for example, transitioning to cirrostratus — the probability of precipitation in the following 12 to 24 hours increases. When occurring in isolation and without any tendency toward thickening, the cloud is of lesser meteorological significance, merely indicating moisture at altitude. For aviation, cirrus floccus is an indicator of possible light to moderate turbulence in the upper troposphere.
Facts
- WMO-Code
- Ci flo
- Height layer
- High clouds
- Typical height
- 6.0 - 12.0 km
- Genus
- CIRRUS