Cumulus humilis
Cu hum
Cumulus humilis
© Wetterkurs.ch
Description
The name "humilis" (Latin: low, modest) describes the limited vertical extent of this cloud species. Cumulus humilis are flat, small cumulus clouds whose vertical extent is significantly less than their horizontal extent. They typically form through weak thermal convection on sunny days and are therefore often referred to as "fair-weather clouds." Their tops are slightly domed, while the bases appear relatively flat and sharply defined. They frequently occur during the morning and early afternoon hours and usually dissipate again towards evening.
Identification Features
- Flat, wide cumulus clouds with limited vertical extent
- Horizontal extent is significantly greater than vertical extent
- Sharply defined, flat cloud base
- Slightly domed, cauliflower-shaped tops, but without strong towering
- White to light grey colouring, rarely with dark shading
- Often appear in groups or fields with regular spacing
- Typical appearance on sunny days with light thermals
- No precipitation formation visible
Occurrence by genus
Highlighted: all genera with which humilis occurs.
Meteorological Significance
Cumulus humilis are regarded as classic fair-weather clouds and indicate stable atmospheric conditions with limited convection. Their presence points to dry air in the middle troposphere, which prevents further vertical growth. As long as they remain flat and do not transition into the species "mediocris" or "congestus," precipitation is generally not to be expected. However, growth throughout the day can indicate increasing atmospheric instability and may signal the possible later development of showers or thunderstorms. If the clouds dissipate towards evening, the weather generally remains settled.
Facts
- WMO-Code
- Cu hum
- Height layer
- Vertical clouds
- Typical height
- 0.6 - 2.0 km
- Genus
- CUMULUS