While clouds show up in unlimited shapes and also sizes they loss into some straightforward forms. From his Essay of the changes of Clouds (1803) Luke Howard separated clouds into three categories; cirrus, cumulus and also stratus.

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Cirro-formThe Latin indigenous 'cirro' method curl that hair. Composed of ice crystals, cirro-form clouds room whitish and also hair-like. There space the high, wispy clouds to first appear in advance of a low-pressure area such as a mid-latitude storm device or a tropical device such as a hurricane.
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Cumulo-form
Generally detached clouds, they look favor white fluffy noodle balls. They display vertical activity or thermal uplift the air ensuing in the atmosphere. They space usually thick in appearance through sharp outlines. The basic of cumulus clouds are normally flat and also occurs at the altitude whereby the moisture in rising air condenses.
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Strato-form
From the Latin word because that 'layer' these clouds space usually wide and relatively wide spread showing up like a blanket. They result from non-convective rising air and tend to take place along and to the north of warmth fronts. The edge of strato-form clouds room diffuse.
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Nimbo-form
Howard likewise designated a special rainy cloud group which combined the three develops Cumulo + Cirro + Stratus. He called this cloud, 'Nimbus', the Latin word because that rain. The vast majority of precipitation wake up from nimbo-form clouds and therefore this clouds have the biggest vertical height.

The elevation of Clouds

The traditional division between the Polar and Temperate areas is the Arctic circle (66.5°N) in the north Hemisphere and the Antarctic one (66.5°S) in the southerly Hemisphere. The department between the Temperate and also Tropical regions are the Tropics that Cancer (23.5°N) in the north Hemisphere and also the Tropics the Capricorn (23.5°S) in the southern Hemisphere.

The actual division between these areas varies from day come day and also season to season. Between the Polar and Temperate areas lies the jet stream in both hemispheres, if the Sub-Tropical Jet present divides the Temperate and also Tropical Regions.

One result of this cores of solid wind is the preferably altitude that the tropopause to reduce in each an ar as one moves from the equator to the poles. Generally, as the tropopause's height decreases, the elevations at which clouds occur also decreases.

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The exception is for low clouds which room officially stated to have actually cloud bases in ~ the first 6,500 feet (2,000 meters) of the surface in every region. However even the is not always the case.

The basic of cumulus and also cumulonimbus clouds have the right to sometimes be higher than 6,500 feet (2,000 meters). During summertime, the basic of these convective clouds will certainly be fine in to the mid-level cloud variety in the non-mountainous areas of the southwest united States.

Cumulus cloud bases have been observed up to 9,000 feet (2,750 meters) end North main Texas and also thunderstorms, v cloud bases indigenous 11,000 to 12,000 feet (3,350 come 3,650 meters), have developed near mountain Angelo, Texas.

This wake up when, in spite of the dry reduced level the the atmosphere, the atmosphere in the mid-levels is relatively moist and also unstable. The dryness the the reduced level is such the parcels the air need to rise up to two miles (3 km), and also sometimes more, prior to the lock cool to the point of condensation.

LevelPolar RegionTemperate RegionTropical RegionHigh CloudsMid CloudsLow Clouds
10,000-25,000 feet (3-8 km)16,500-45,000 Feet (5-14 km)20,000-60,000 feet (6-18 km)
6,500-13,000 feet (2-4 km)6,500-23,000 feet (2-7 km)6,500-25,000 feet (2-8 km)
Surface-6,500 feet (0-2 km)Surface-6,500 feet (0-2 km)Surface-6,500 feet (0-2 km)

Since the jet stream complies with the sun, the shifts towards the equator as winter progresses. Therefore, the polar region expands and the temperate an ar moves toward the equator. In summer, the Tropical region expands moving the temperate an ar toward the poles when the polar region shrinks.

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The department between these areas varies indigenous day come day and season come season based upon places of the jet and sub-tropical jet streams.

Learning Lesson: A 'Hole' most Clouds 1