Cloud Formation and Type
Formation of Clouds
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Form as warm (low pressure) is forced upward, expands, and cools
(high pressure).

Cooling reduces the amount of water vapor needed for saturation
and the relative humidity increases

Water vapor forms tiny droplets around small particles (dust and
salt)

These droplets of water are so small that they remain suspended in
the air- BILLIONS of these droplets form a cloud.
Classification

Identified by size and height.

Dense clouds = rain and snow; thin and wispy appear on sunny days.

Shape and height vary with temperature, pressure, and the amount of water vapor
Types of Clouds
Cirrus- fibrous or curly
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They are high, thin, white, feathery clouds made of ice crystals.
–
Associated with fair, sunny weather, but they can sometimes
indicate approaching storms.
Cumulus- puffy, white clouds, often with flat bases
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Vertical—can be up to 18km tall
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Associated with fair weather or thunderstorms
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These are the type of clouds you make figures out of.
Stratus- Shape horizontally
-
Form at low altitudes
Associated with fair weather, RAIN, or SNOW
When air is cooled to its dew point near the ground it forms a stratus cloud called
FOG.
Prefixes

Prefixes help us also determine other types of clouds.
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Cirro = high clouds
–
Alto = middle level clouds
–
Strato = low elevation
High Level Clouds

Cirrocumulus: fluffy, high, cotton-type clouds

Cirrostratus: thin sheets, high whitish layers of clouds
Middle Level Clouds

Altocumulus: Rounded layers or patches of clouds, middle of the sky

Altostratus: Gray, streaked layers of clouds, middle of the sky

Nimbostratus: Mid-level, thick, gray layers of clouds bring rain and snow
–
(NIMBO = “rain”)
Low Level Clouds
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Stratocumulus: Layers of cumulus clouds, low
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Cumulonimbus: Large, dark, billowing clouds