Cloud Classification Flashcards
What cloud category is a flat, layered and smooth?
Stratus/strato
What cloud category is heaped up, puffy?
Cumulus/cumulo
What cloud category is feathery, wispy?
Cirrus/cirro
What cloud category is rain-bearing?
Nimbus/nimbo
Which cloud category is mid-level?
Alto
What level are high-level clouds?
5,000m/16,500ft
What level are mid-level clouds?
2000m-7000m/6,500ft-23,000ft
What level are low-level clouds?
Up to 2,000m/6,500ft
What would a cloud below -40 degrees compose of?
Almost entirely ice particles
What would a cloud between -10 and -40 degrees compose of?
Mixture of supercooled water droplets and ice crystals
What would a cloud between 0 and -10 degrees compose of?
Almost entirely supercooled water droplets
What would a cloud above 0 degrees compose of?
Water droplets
Detached clouds in the form of white, delicate filaments or white/mostly white patches/narrow bands. Fibrous/silky sheen appearance.
Cirrus (Ci)
Thin, white patch, sheet/layer of cloud without shading, composed of very small elements in the form of grains/ripples. Merged or separate and more or less regularly arranged. Most elements have apparent width of less than 1 degree.
Cirrocumulus (Cc)
Transparent, whitish cloud veil of fibrous/smooth appearance, totally or partly covering the sky, produces a halo phenomena.
Cirrostratus (Cs)
White/grey or white and grey, patch, sheet or layer of cloud, with shading, composed of layers, rounded masses, rolls. Sometimes partly fibrous which may or may not be merged, most of the regularly arranged small elements have a width between 1 and 5 degrees.
Altocumulus (Ac)
Grey/blue cloud sheet/layer of striated, fibrous/uniform appearance, totally or partly covering the sky, having parts thin enough to reveal the sun, does not show halo phenomena.
Altostratus (As)
Grey/whitish, or both, patch, sheet or layer of cloud that almost always has dark parts. Composed of tessellations, rounded masses, rolls which are non-fibrous, may or may not be merged, small elements have a width more than 5 degrees.
Stratocumulus (Sc)
Generally grey cloud layer with a fairly uniform base, may give drizzle, snow or snow grains. When the sun is visible its only the outline. No halo phenomena except possibly at very low temperatures.
Stratus (St)
Grey cloud layer, often dark. More or less continuous falling rain or snow. Thick enough to block out the sun.
Nimbostratus (Ns)
Detached clouds generally dense and with sharp outlines, developing vertically in the form of rising mounds, domes or towers, of which the bulging upper part often resembles a cauliflower. Clouds are mostly brilliant white with the bases dark and nearly horizontal.
Cumulus (Cu)
Heavy and dense clouds with a considerable vertical extent, in the form of a mountain or huge towers. At least part of its upper portion is usually smooth, fibrous or striated and nearly always flattened, this part spreads out in the shape of an anvil o vast plume. Under the base it is often very dark.
Cumulonimbus (Cb)
Which clouds can be castellanus?
Ci, Cc, Ac and Sc (cumuliform clouds)
What is the name for clouds that produce turrets or towers?
Castellanus
High clouds can be lenticularis?
Cc, Ac and Sc
What is the name of clouds that have the shape of lenses or almonds, often very elongated and usually well-defined outlines. Most often associated with clouds of orographic origin?
Lenticularis
Which clouds can be congestus?
Cu
What are clouds that are strongly sprouting, sharp outlines and often great vertical extent. The bulging upper part frequently resembles a cauliflower?
Congestus
What is a Cumulus congestus of great vertical extent?
Towering Cumulus (TCu)
What is a Cb called when the upper parts are beginning to lose their cumuliform outlines but no cirriform parts can be distinguished?
Cb calvus
What is a Cb called where its upper portion, of distinct cirriform parts having the shape of an anvil?
Cb Capillatus
How are cloud amounts measured?
Oktas
How many oktas are FEW?
1-2
How many oktas are SCT?
3-4
How many oktas are BKN?
5-7
How many oktas are OVC?
8
What is the VFR visibility minima?
Cloud ceiling more than 450m/1500ft
Ground visibility more than 5km
