Bioprecipitation, the concept of rain-making bacteria, was proposed by David Sands from Montana State University. Such microbes – called ice nucleators – are found in rain, snow, HP Pavilion dm4-1008tu Battery and hail throughout the world. These bacteria may be part of a constant feedback between terrestrial ecosystems and clouds and may even have evolved the ability to promote rainstorms as a means of dispersal. They may rely on the rainfall to spread to new habitats, much as some plants rely on windblown pollen grainsHP Pavilion dm4-1008tx Battery.
Species cirrocumulus stratiformis (Cc str): Sheets or relatively flat patches of cirrocumulusHP G62-a30SA Battery.
Species cirrocumulus lenticularis (Cc len): Lens-shaped cirrocumulus.
Species cirrocumulus castellanus (Cc cas): Turreted cirrocumulus.
Species cirrocumulus floccus (Cc flo): Tufted cirrocumulus.
Opacity-based varieties: None. HP G62-a38EE Battery
Pattern-based varieties: Undulatus, lacunosus.
Precipitation-based supplementary feature: Virga.
Accessory cloud: Mamma.
Mother clouds -genitus: None; -mutatus: Cirrus, cirrostratus, altocumulus. HP G62-a40SA Battery
Genus cirrostratus (Cs): A thin non-convective ice crystal veil that typically gives rise to halos caused by refraction of the sun’s rays. The sun and moon are visible in clear outline. Cirrostratus typically thickens into altostratus ahead of a warm front or low-pressure area. HP G62-a43SA Battery
Species cirrostratus fibratus (Cs fib): Fibrous cirrostratus less detached than cirrus (CH8).
Species cirrostratus nebulosus (Cs neb): A featureless veil of cirrostratus (CH7).
Opacity-based varieties: NoneHP G62-a44EE Battery.
Pattern-based varieties: Duplicatus, undulatus.
Precipitation-based supplementary features: None.
Accessory clouds: None.
Mother clouds -genitus: Cirrocumulus, cumulonimbus; -mutatus: Cirrus, cirrocumulus, altostratus. HP G62-a44SA Battery
Middle (Family B)
Family B middle clouds over Santa Clarita, CA. Altocumulus floccus producing virga near top and middle of image merging into altostratus near horizon. HP G62-a45SA Battery
Middle clouds tend to form at 6,500 ft (2,000 m) but may form at heights up to 13,000 ft (4,000 m), 23,000 ft (7,000 m) or 25,000 ft (7,600 m) depending on the latitudinal region. In general, the warmer the climate the higher the cloud base. Family B usually comprises one cumuliform and one stratiform-category genus. HP G62-a50SG Battery 
Family B includes:
Genus altocumulus (Ac): A cloud layer of limited convection usually in the form of irregular patches or rounded masses in groups, lines, HP G62-a53SG Batteryor waves. High altocumulus may resemble cirrocumulus but is usually thicker and composed of water droplets so that the bases show at least some light-grey shading. Opaque altocumulus associated with a weak frontal or low-pressure disturbance can produce virga, very light intermittent precipitation that evaporates before reaching the ground. HP G62-a60SA BatteryIf the altocumulus is mixed with moisture-laden altostratus, the precipitation may reach the ground.