Download Clouds: Cumulus, Stratus, Cirrus

Name That Cloud
Clouds: Stratus, Cirrus, Cumulus
By: Eva Reyes, Taylor Griffith, Sandy Bobbitt, Diana Jones
Definitions
1.Air
The air is the invisible gaseous substance surrounding the earth, a
mixture mainly of oxygen and nitrogen.
1. Cloud
A visible collection of tiny water droplets or, at colder
temperatures, ice crystals floating in the air above the surface.
Clouds come in many different sizes and shapes. Clouds can form
at ground level, which is fog, at great heights in the atmosphere,
and everywhere in between. Clouds offer important clues to
understanding and forecasting the weather.
2.Precipitation
General name for water in any form falling from clouds. This
includes rain, drizzle, hail, snow and sleet. Although, dew, frost
and fog are not considered to be precipitation.
What are clouds?
A cloud is a large collection of very tiny droplets of water or ice crystals. The droplets are so small
and light that they can float in the air.
How are clouds formed?
All air contains water, but near the ground it is usually in the form of an invisible gas called water
vapor. When warm air rises, it expands and cools. Cool air can't hold as much water vapor as warm
air, so some of the vapor condenses onto tiny pieces of dust that are floating in the air and forms a
tiny droplet around each dust particle. When billions of these droplets come together they become
a visible cloud.
Clouds form when humid air cools enough for water vapor to condense into droplets or ice crystals.
The altitude at which this happens depends on the humidity and the rate at which temperature
drops with elevation.
Stratus Clouds
 Stratus clouds are uniformed layered clouds that are below
6,000 feet.
 They are formed in sheets and are usually associated with
overcast weather.
 Fog or mist is the result of very low stratus clouds.
 Stratus clouds are more known for drizzle than for precipitation.
 Stratus clouds are formed when a weak upward air current
lifts a thin layer of air high enough to start condensation of the
excess water vapor if the air temperature falls below the dew
point.
Stratus Clouds
•
•
Stratus clouds are uniform grayish clouds
that often cover the entire sky
Four Types of Stratus Clouds
Altostratus Clouds
 Altostratus clouds appear in altitudes of 6,000 to 20,000 feet.
 They are very thin and uniform, and are gray or blue-gray,
creating overcast.
 Altostratus clouds are associated with coming rain, and they
usually cover most, if not all, of the sky. Altostratus clouds can’t
produce heavy precipitation, but they are often the cause of a
light drizzle.
Nimbostratus clouds
 Nimbostratus clouds form at or below 6,000 feet.
 They are dark, low clouds that bring light to heavy
prolonged precipitation, such as snow or rain.
 Nimbostratus clouds that are broken up are called
fractostratus clouds.
Fractostratus Clouds
Low ragged layered cloud often appearing below nimbostratus
clouds during rain.
Angry Cloud Video
http://www.youtube.com/
watch?v=gdg6WU_aqWE
Cirrus Clouds
 Cirrus clouds are the most common of
the high clouds. They are composed of ice
and are thin, wispy clouds
 Cirrus clouds are usually white and predict
fair to pleasant weather.
 By watching the movement of cirrus
clouds you can tell from which direction
weather is approaching.
 When you see cirrus clouds, it usually
indicates that a change in the weather
will occur within 24 hours
Cirrus Cont.
 Cirrus clouds look thin because they are made of ice
crystals, not water drops.
 They form where it is high enough to be cold and
freeze the water drops into ice.
Types of Cirrus Clouds
 Cirrostratus clouds are thin,
sheetlike high clouds that
often cover the entire sky.
Cirrostratus clouds usually
come 12-24 hours before a rain
or snow storm.
 Cirrocumulus clouds appear as
small, rounded white puffs that
appear in long rows. Cirrocumulus
clouds are usually seen in the
winter and indicate fair, but cold
weather. In tropical regions, they
may indicate an approaching
hurricane.
Cumulus Clouds
The bright lights of Tucson, Arizona, are more than matched by a flash of lightning far above the city
skyline. The sunset scene shows a classic cumulonimbus cloud formation.
Physical Description
 Cumulus clouds are puffy
clouds that sometimes look
like pieces of floating cotton.
 The base of each cloud is
often flat and may be only
1000 m above the ground.
 The tops have rounded
towers.
 These clouds form below
6000 ft. (extreme cases they
can be as high as 39,000).
Cumulus Congestus Clouds
 When the top of a cloud looks like cauliflower, it
is called a cumulus congestus or towering
cumulus.
 These clouds grow upward and they can
develop into a giant cumulonimbus, which is a
thunderstorm cloud.
Cumulonimbus Clouds
 These are severe weather
clouds and often have the
potential to generate heavy
rain, strong winds, severe
lightening, damaging hail
and deadly tornadoes.
http://www.youtube.com/wat
ch?v=exlVSEPEXKc
The Weather of Cumulus Clouds
 Typical cumulus clouds are usually associated with fair
weather
 Congestus cumulus clouds often grow large enough to
produce short and strong periods of rain.
 Cumulonimbus clouds are likely to bring thunderstorms and
tornadoes.
Tornadoes
 Tornadoes are among Earth's most violent natural acts. About a thousand of
them touch down in the United States each year, more than in any other
country in the world. Some are wispy and last only seconds, others rampage
across the landscape for more than an hour, but few are as destructive as
the one that obliterated Manchester.
 By definition tornadoes are rotating columns of air that extend from
swelling cumulonimbus clouds to the ground. No one fully understands
tornado dynamics, but certain ingredients seem essential to the witches'
brew from which twisters emerge: warm, humid air near the ground, colder
air aloft, and shearing winds that change direction and speed with height.
The most destructive and deadly tornadoes form under the bellies of super
cells, large long-lived thunderstorms whose winds are already in rotation.
 http://science.nationalgeographic.com/science/earth/earthsatmosphere/chasing-tornadoes-earth/#page=2
http://www.youtube.com/watch?v=0
06guBgSf14
http://www.youtube.com/watch?v=D
1IV6INfqfA
NAME THAT CLOUD
Characteristics:
• High Clouds
• Thin & Wispy
• Fair to pleasant weather
Cirrus
 Characteristics:
 Associated with
overcast weather.
 uniform grayish clouds
that often cover the
entire sky
 Lower clouds
Stratus
Characteristics:
• puffy clouds that
sometimes look like
pieces of floating
cotton
• Can produce severe
weather