Weather 101: Clouds
Clouds are an ever-changing aspect of weather. Clouds can often be a great visual indicator
of certain weather patterns, and they can even act as a harbinger of upcoming weather
conditions. In this brief tutorial, we will discuss four primary types of clouds, as well
as some combinations or hybrids within these categories. We’ll show some specific examples
of each, and some of the weather elements associated with these different cloud types.
Clouds are categorized by their structural characteristics and the height in the atmosphere
at which they develop. The four main forms of clouds are cirro-form, cumulo-form, strato-form,
and nimbo-form. There can be different combinations or hybrids of these cloud types.
Cirrus clouds are high level clouds that typically form between 16,000 and 50,000 feet above
the surface. The Latin word “cirro” means curl of hair. Many times cirrus clouds can
mimic curls of hair due to the thin, wispy structure they exhibit. “Cirro” can also
be used as a prefix to describe high level clouds. Cirrus clouds are composed of tiny
ice crystals suspended in the upper parts of the troposphere, the layer of the atmosphere
where all weather occurs. Cirrus clouds are often thought of as “indirect” indicators
of weather patterns. Sometimes they may accompany a strong jet stream in the upper atmosphere.
Cirrus clouds can also be seen preceding surface fronts by more than a day or two.
Cumulus clouds might be one of the more recognizable cloud types. “Cumulo” is Latin for heap
or pile. Cumulus clouds often are detached or isolated from other clouds, and will often
appear as fluffy white cotton balls or perhaps even cauliflower. These clouds are considered
low level clouds, usually forming between a few hundred to a few thousand feet above
the surface. In the desert Southwest and much of New Mexico these cloud bases will often
form at higher levels than other parts of the country due to the warm and arid conditions.
Strato-form clouds or layer clouds often appear as a sheet or layer of cloud that exhibits
little definition or features. In other words they will typically appear as a hazy white
or gray mass. Stratus clouds are primarily thought of as low clouds, but can be observed
in the middle to upper parts of the atmosphere as well. Mid level stratus clouds are referred
to as altostratus and high level stratus are commonly identified as cirrostratus.
Nimbo-form clouds are also representative of a hybrid or combination of different cloud
categories. “Nimbo” is Latin for rain. The two common nimbo-form cloud types are
nimbostratus and cumulonimbus. As you can probably guess, nimbostratus clouds are layered,
producing rain or precipitation. These clouds can extend into the middle to upper parts
of the troposphere, but are typically only seen in the lower parts since they will usually
obscure any clouds above. Cumulonimbus are also a unique hybrid of cloud that extends
from the lower to the upper parts of the troposphere and are otherwise known as thunderstorm clouds.
We briefly mentioned cirrostratus, but another high level cloud is cirrocumulus. These are
similar to altocumulus, the difference being that altocumulus form in the mid levels of
the troposphere while cirrocumulus clouds are in the highest part of the troposphere.
Altocumulus clouds have some variations of their own.
One such variation that frequents New Mexico is the altocumulus standing lenticular, sometimes
simply referred to as lenticular, lennies, or wave clouds. These clouds are common on
the leeward side of topographical barriers such as mountains where a stable layer of
air is found above the crest or peaks of the topography.
Stratocumulus clouds are another combination of two previously mentioned categories: stratus
So, we’ve discussed a few of the more common cloud types. We invite you to scan the skies,
and maybe you can identify a few of these cloud types on your own. For more information
refer to the National Weather Service website, including the “Jetstream” website where
you can learn more about clouds with additional charts and imagery.