Transcript Clouds

Clouds
Amber and James
How are clouds formed?
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Clouds form by condensation.
The sun heats the earth and the air above it.
This warmer air will rise up into the atmosphere.
As the air rises, it cools because it’s expanding, but it is
traveling further away from the heat source.
The air will cool to its dew point, the air is saturated and
the water vapor can condense into tiny particals called
condensation nuclei.
When enough droplets condense, and the clouds become
visible.
Altitude
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High level clouds are about 20,000 feet.
Mid-level clouds appear between 6,500 to
20,000 feet.
Low level clouds lie below 6,500 feet.
Vertically Developed clouds can grow to
heights in excess of 39,000 feet.
Cirrus Clouds
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They tend to have
feathery strands called
mares' tails.
These often indicate the
approach of a warm front
marking the advance of a
storm system.
Whenever there is
moisture in the upper
levels of the atmosphere,
cirrus clouds will usually
form.
Cirrocumulus
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They are small rounded
puffs that usually appear in
long rows.
If these clouds cover a lot of
the sky, it is called a
"mackerel sky" because the
sky looks like the scales of
a fish. Cirrocumulus are
usually seen in the winter
time and indicate fair, but
cold weather.
Cirrostratus
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Cirrostratus indicate a
significant amount of moisture
in the higher levels of the
atmosphere.
A layer of wide spread
cirrostratus may indicate one
of two things.
The first being the approach
of an active disturbance.
The second being an inactive
high level moisture outflow.
Altocumulus
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Cover a large area for a
long time.
indicate an active moving
weather system
If cloud layers at other
levels can also be seen,
an organized weather
system may be
approaching the area.
Altostratus
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form when there is a
significant amount of
moisture present.
These clouds often
are carried long
distances without
significant change.
Stratus
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Very little precipitation
ever falls from stratus
clouds.
they appear very large
since they are so close to
the ground.
Stratus clouds also
represent the transition to
or from fog and cumulus
clouds.
Stratocumulus
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may occur often
along coasts.
the clouds accompany
larger scale weather
systems
Stratus clouds
indicate low level
moisture.
Nimbostratus
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Nimbostratus clouds
are precipitation
clouds.
Nimbostratus clouds
should be watched
closely because most
thunderstorms start
with a nimbostratus
phase.
Small Cumulus &Swelling Cumulus
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Cumulus clouds are fair weather
clouds.
If they are seen in the afternoon,
there is no threat of showers.
called towering cumulus.
They are taller than they are
wider.
For a swelling cumulus to
develop, there must be some
instability in the atmosphere.
The earlier in the day these clouds
start the form, the larger the threat
of strong storms later in the day.
Cumulonimbus
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Cumulonimbus clouds
are thunderstorm clouds.
Precipitation is always
present with these
clouds.
Often, severe weather
will occur.
develop from swelling
cumulus.
When lightning and
thunder are detectable,
the cloud is a
cumulonimbus.
Mammatus
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Mammatus clouds are
an indication of very
severe weather.
Large mammatus
clouds indicates that
there is a very strong
thunderstorm near by.
The pouch like
structures are a result
of sinking air.
Lenticular Clouds
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These clouds form as
air passes over
mountains.
to form the air must
be fairly dry yet still
contain some
moisture.
air will move in a
smooth arc over the
mountain.
Kelvin-Hemholtz Clouds
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These clouds which have
the appearance of
breaking waves usually
last for a few seconds to a
few minutes.
In other words they
indicate a large change in
wind
Caused by speed over a
small increase in altitude.
Fog
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Fog is a dense cloud of water
droplets, or cloud, that is close
to the ground.
The moister in the air
condenses and forms
advection fog, or “land fog”.
Another type of fog is sea fog,
which is carried from place to
place on air currents, it hardly
ever dissipates because it
continuously forms.