Stratiform

Stratiform
Nonconvective stratiform clouds appear in stable airmass conditions and, in general, have flat, sheet-like structures that can form at any altitude in the troposphere.[32] The stratiform group is divided by altitude range into the genera cirrostratus (high-level), altostratus (mid-level), stratus (low-level), and nimbostratus (multi-level).[4] Fog is commonly considered a surface-based cloud layer.[21] The fog may form at surface level in clear air or it may be the result of a very low stratus cloud subsiding to ground or sea level. Conversely, low stratiform clouds result when advection fog is lifted above surface level during breezy conditions.

Stratocumulus over Orange County.
Cirriform
Cirriform clouds in the troposphere are of the genus cirrus and have the appearance of detached or semimerged filaments. They form at high tropospheric altitudes in air that is mostly stable with little or no convective activity, although denser patches may occasionally show buildups caused by limited high-level convection where the air is partly unstable.[33] Clouds resembling cirrus can be found above the troposphere but are classified separately using common names.

Stratocumuliform
Clouds of this structure have both cumuliform and stratiform characteristics in the form of rolls, ripples, or elements.[5] They generally form as a result of limited convection in an otherwise mostly stable airmass topped by an inversion layer.[34] If the inversion layer is absent or higher in the troposphere, increased airmass instability may cause the cloud layers to develop tops in the form of turrets consisting of embedded cumuliform buildups.[35] The stratocumuliform group is divided into cirrocumulus (high-level), altocumulus (mid-level), and stratocumulus (low-level).[5]