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Weather
Temperature
• Temperature is the
measure of the amount
of thermal energy in the
atmosphere.
• How cold or how warm
the air is what we call
the temperature!
Air Pressure
• Air pressure is due to
the weight of the air
and is determined by
several factors including
the temperature of the
air.
Barometer
• An instrument called a
barometer measures air
pressure.
Weather Front
• A weather front is the
boundary between air
masses of different
temperature and
humidity.
Types of Clouds
• Cirrus, stratus, cumulus,
and cumulo-nimbus
clouds are associated
with certain weather
conditions.
Types of Clouds
• Cirrus clouds - Cirrus
clouds are feathery
clouds.
• They are associated
with fair weather.
• Cirrus clouds often
indicate that rain or
snow will fall within
several hours.
Types of Clouds
• Stratus clouds - Stratus
clouds are smooth, gray
clouds that cover the
whole sky (block out
direct sunlight).
• Light rain and drizzle
are usually associated
with stratus clouds.
Types of Clouds
• Cumulus clouds Cumulus clouds are
fluffy and white with
flat bottoms.
• They usually indicate
fair weather.
Types of Clouds
• However, when
cumulus clouds get
larger and darker on the
bottom, they become
cumulo-nimbus clouds.
• Cumulo-nimbus clouds
may produce
thunderstorms.
Precipitation
• Precipitation – Water
that falls from the
clouds to the Earth in
the form of rain, snow,
hail, or sleet.
• Different atmospheric
conditions create
different types of
precipitation.
Rain
• Rain – When cloud
droplets become too
heavy to stay in the
cloud, they fall toward
the Earth’s surface as
liquid water.
• Rain Gauge – An
instrument used to
measure the amount of
precipitation.
Sleet
• Sleet – When a falling
snowflake melts by
passing through warm
air, and then suddenly
refreezes by passing
through cold air, it
becomes a tiny chunk of
ice called sleet.
Snow
• Snow – Tiny ice crystals
attract each other as
they fall toward the
ground.
• Since the snowflakes do
not pass through a layer
of air warm enough to
cause them to melt,
they remain intact and
reach the ground as
snow.
Hail
• Hail – These big frozen raindrops occur during
severe thunderstorms.
• Cold air turns a raindrop into a tiny chip of ice.
• Violent winds push the drop back up into the
cloud to be coated over and over again with more
layers of ice.
• Eventually, the hailstone is heavy enough to fall
to the ground!
Extreme Storms
• There are three main
types of extreme
storms.
• They include
thunderstorms,
tornadoes, and
hurricanes.
• Anemometer – A tool
that measures wind
speed.
Thunderstorms
• Thunderstorm – When
cumulo-nimbus clouds
are joined by strong
winds, heavy rains, and
sometimes hail.
• Lightning is also a major
feature of many
thunderstorms.
Hurricanes
• Hurricane – A huge,
slow-moving storm that
is fueled by heat and
energy from warm
ocean waters.
• Some hurricanes can be
over 500 miles wide
and have winds over
150 miles per hour!
Tornadoes
• Tornado – A dangerous
funnel-shaped column
of air that reaches from
a thundercloud to the
ground.
• It has spinning winds
that can reach over 250
miles per hour!
Meteorologists
• Meteorologist – A
scientist who studies
the weather.
• They use many tools to
help them predict and
identify the weather.
• Meteorologists use data
to predict weather
patterns.