Cumulus humilis
Cumulus humilis is a low, shallow cumulus cloud with little vertical development, commonly associated with fair weather.
Cumulus cloud: A cloud with distinct, often rounded elements and a flat or gently curved base, formed by rising air. Cumulus humilis is the shallowest, least vertically developed form in this cloud family.
Convective condensation level: The height at which air heated from the surface, rising dry adiabatically, becomes saturated and forms convective cloud. Surface heating can lift air to this level and initiate shallow cumulus formation.
Cumulus fractus: A ragged, fragmented cumulus cloud, often produced by turbulent or rapidly changing air. Its broken appearance contrasts with the more coherent, flat-based humilis cloud.
Cloud observation: The systematic visual identification and recording of cloud types and their changing forms. Observers classify humilis clouds by their shallow profile and distinct outline.
Cloud base: The lowest visible boundary of a cloud, marking the altitude where air becomes saturated. Its flat underside reflects the lifting condensation level of the rising air.
Dry adiabatic lapse rate: The rate at which unsaturated air cools as it rises without exchanging heat with its surroundings. Rising thermals cool at this rate before reaching saturation and forming cloud.
Cumulus mediocris: A cumulus cloud of moderate vertical development, taller than humilis but usually lacking strong precipitation. It is the next common step in cumulus growth beyond humilis.
International Cloud Atlas: The World Meteorological Organization's reference for cloud classification, description, and imagery. It defines the official characteristics used to identify Cumulus humilis.
Atmospheric convection: Vertical heat transfer in the atmosphere through the motion of warmer and cooler air. Small convective currents produce the limited upward growth characteristic of this cloud.
Atmospheric stability: The tendency of the atmosphere to resist or encourage vertical displacement of air. Stable air above the cloud layer limits the thermals' vertical development.