Transcript weather - Wboro5thGrade

Weather
The condition of air on earth at any given
time or place- whether its warm or cold,
dry or wet, blowing or calm.
Weather starts with the sun. The sun’s heat
warms our atmosphere and causes two
things to happen:
1. Water evaporates into the air
2. Air rises
Predictable Patterns of Weather
continued…
Precipitation: depends on the temperatures of the ground
and atmosphere.
Wind speed and direction: help determine unequal
heating or air masses, and is also related to air pressure
differences.
Temperature: Affected by many factors
Cloud Cover: caused by pressure systems and can
change precipitation and temperature.
Weather Smart: Forecasting and Weather Instruments (United Streaming)
Weather and Climate Facts:

Weather and climate are usually related to: rain,
clouds, storms, wind and temperature.
 Water is the main factor (water on Earth are
constantly interacting, changing and moving)
 Clouds also play and very important role when
talking about humidity, wind, temperature,
geography and precipitation. They can also be
linked to specific weather conditions.
 Climate patterns: help determine types of
weather in different regions.
Review: Water Cycle
Evaporation: Evaporation is when the sun heats up
water in rivers or lakes or the ocean and turns it
into vapor or steam. The water vapor or steam
leaves the river, lake or ocean and goes into the
air.
Condensation: Water vapor in the air gets cold and changes
back into liquid, forming clouds. This is called
condensation.
You can see the same sort of thing at home... pour a glass of
cold water on a hot day and watch what happens. Water
forms on the outside of the glass. That water didn't
somehow leak through the glass! It actually came from the
air. Water vapor in the warm air, turns back into liquid
when it touches the cold glass.
Weather Smart: The Water Cycle and
Clouds
Precipitation: Precipitation occurs when so
much water has condensed that the air
cannot hold it anymore. The clouds get
heavy and water falls back to the earth in
the form of rain, hail, sleet or snow.
Groundwater/Runoff: When the precipitation
falls to the ground and is either soaked into
the ground or runs off into rivers, oceans or
lakes.
Water Cycle Songs (Tune of She’ll
be Coming Around the Mountain)
(Song to the tune of , It’s Raining, It’s Pouring.)
ITS RAINING, ITS POURING
THE OCEANS ARE STORING,
WATER FROM THE FALLING RAIN
WHILE THINDERCLOUDS ARE ROARING
THE RAIN NOW IS STOPPING
THE RAIN’S NO LONGER DROPPING
SUN COMES OUT AND SOAKS UP WATER
LIKE A MOP THAT’S MOPPING
THE WATER’S STILL THEE NOW
BUT HIDDEN IN THE AIR NOW
IN THE CLOUDS IT MAKES A HOME
UNTIL THIERE’S RAIN TO SHARE NOW
REASONS FOR SEASONS

THE EARTH IS TITLED ON AN AXIS AT THE NORTH AND
SOUTH POLE AND THIS CREATES THE SEASONS.

THE IMAGINARY LINE RUNNING THROUGH THE MIDDLE OF
THE EARTH IS CALLE D THE EARTH’S AXIS/EQUATOR.

ANOTHER REASON WE HAVE DIFFERENT SEASONS IS
BECAUSE THE EARTH MOVES AROUND THE SUN SO THE
NORTH POLE IS EITHER FACING TOWARD THE SUN OR AWAY
FROM THE SUN.

THE EARTH’S TILT CAUSES DIFFERENT AMOUNT OF
SUNLIGHT TO REACH THE EARTH AT DIFFERENT TIMES IN
THE YEAR. THE NORTHERN HEMISPHERE GETS MORE
DIRECT SUNLIGHT IN THE SUMMER BECAUSE THE SOUTERN
HEMSPHERE IS TITLTED AWAY FROM THE SUN THEY ARE
HAVING THEIR WINTER.

NEAR THE EQUATOR, THE EARTH DOESN’T HAVE WINTER
OR SUMMER. THE WEATHER BARELY CHANGES AT ALL.
REVOLUTION AND ROTATION

REVOLUTION: EARTH MOVING IN A PATH
AROUND THE SUN, RESULTING IN ONE
EARTH YEAR.
 ROTATION: THE EARTH SPINNING AROUND
EVERY 24 HOURS, RESULTING IN DAY AND
NIGHT.
Weather and Geography
There are many geography factors that
affect weather and climate. They include:
1.
2.
3.
4.
5.
Latitude
Altitude
Winds
Distance from the sea
Urbanization/living in the city
Latitude: The distance from the equator can
determine weather and climate.
As you move closer to
the equator the
temperature
increases. The farther
away you are from the
equator the
temperature
decreases. This is due
to the sun’s rays.
Earth has three major climate zones. These zones are determined by
latitude, or their position on Earth in relation to the equator
Altitude: The farther up you go the temperature
decreases and it gets cold. Air is less dense and
cannot hold the heat.
Notice that there is
snow at the top of
this mountain. The
higher up you go
the colder it
becomes.
Therefore,
mountain regions
have colder
temperatures.
Distance from the sea and bodies of water: The closer
you are to the ocean the cooler the temperature.
.
Water warms and cools much more SLOWLY than land
The temperature of water does NOT change as quickly as
the temperature on land does.
Land near water has milder weather because of the water’s
influence
.
That’s why cities like
Wilmington have cooler
temperatures then cities
like Raleigh.
Bodies of Water
 Lakes
help moderate the temperatures on
the land

The nearby water causes an increase in
moisture in the air, so in the winter these
areas experience heavy snowfall.
Lake Effect
Snow
Urbanization: Living near or in a city also affect the
temperature.
Cities usually have
warmer and
rainier weather
because it is
surrounded by
pavement , larger
building and
factories.
Winds: Depending of where the winds came from, they
can increase or decrease temperature. Example: If cold
winds blow, especially from the north, temperature is
colder. If warm winds blow, usually from the south, the
temperature is warmer.
When wind blows against
a mountain it causes the
air to rise and cool. When
it flows over the mountain
and down the other side
it causes the air to
become cooler and takes
the moisture from the
clouds to create rain.
This is called the rain
shadow effect
Clouds
Clouds consist of billons of tiny water
droplets (and even ice crystals) floating in
the sky and clouds form when rising air
cools and the moisture in it condenses to
water droplets.
Three things are needed for clouds
to form: evaportation, cooling, and
condensation
Clouds can be named by their appearance
or how they look and where they are
located in the sky.

Cirrus: clouds are high, thin, and
wispy white clouds that are made
of tiny ice pieces and they bring
change in the weather.

Stratus: are low, flat gray clouds
which are layered. when stratus
clouds are low to the ground, it
creates fog. These clouds usually
mean rain is coming. .

Cumulus: are white, puffy , clouds
that look like cauliflower and make
fair weather on sunny days.

Cumulonimbus: thunderheads
clouds are huge, puffy, dark
clouds, means heavy rain.
Types of Clouds
Altitude and Cloud Formation
Clouds can also be described by the
altitude/height at which they form. Clouds
that form at high altitudes are described by
the prefix cirro. So stratus clouds that
form high in the sky are called cirrostratus.
 Clouds
that form in the middle of the sky
are described by the prefix alto. A stratus
cloud that forms at a middle altitude is
called an altostratus cloud.
 Alto
cumulus
alto stratus
 Clouds
that form at low altitudes or low in
the sky are described by the prefix strato
so a cumulus cloud that forms at a low
altitude is called a stratocumulus cloud.
Nimbostratus
Guess the Clouds
These clouds form when the wind is strong
CIRRUS
Brings fair weather
Cumulus
Brings thunderstorms
CUMULONIMBUS
Another word for fog
STRATUS
Predictable Patterns of Weather
HIGH pressure: cooler temperatures and
less moisture.
LOW pressure: hotter temperatures and
more moisture
Air Mass
A large body of air that has the same
temperature and level of humidity
throughout.
cool air masses: where the land temperature is cool
warm air masses: form over the land that is warm.
dry air masses: form over dry areas
wet air masses: form over wet areas like oceans.
Fronts
 When
air masses meet, a boundary called
a front is formed, preventing the masses
from mixing.
Fronts
 Two
different types of air masses do not
mix, because of the different densities
 Warm
 When
is less dense than cold air.
warm air and cold air meet, warm
air will rise above cold air.
Cold Front

Cold Front: What is it? At the cold front, the cold air
cuts underneath the warm air and forces the warm air up
a much steeper angle. At cold fonts the air is cooled
quickly and forms a narrow band of thick cumulonimbus
clouds. These produce heavy rain, snow or precipitation.
Cold Fronts bring:
 Heavy
rains
 Thunderstorms
 Sometimes snow
Warm Front
A
warm air mass moves up and over a
cold air mass.
Warm Fronts Bring:
 Rainy,
 Often
drizzly weather
followed by clear, warm weather
Occluded Front
 Two
cold air masses move toward each
other, warmer air between is pushed up
Occluded Fronts Bring:
 Cool
temperatures
 Plenty
of rain
and snow
Stationary Front
 When
a warm and cold air mass meets,
but neither has enough energy to push
against each other
Stationary Fronts Bring:
 Many
days of overcast, rainy weather
Cold Front: A cold air mass
moves under a warm air mass &
pushes the warm air upward. .Cold
fronts bring heavy rain and
thunderstorms and cold weather.
Warm front: forms when warm air
bumps with colder air. This front
brings rainy, drizzly weather, often
followed by warm, clear weather
.
Occluded front: forms when a warm
air mass is caught between two cold air
masses. This brings cool temperatures
and lots of rain and snow.
Stationary front: occurs when a
warm air mass and a cold air mass
meet.. This brings many days of
overcast and rainy weather.
Breezes affect the weather too

Valley breeze: The Sun warms the air above the valley
during the day. The warm air rises and flows up the
mountain.

Mountain breeze: At night the mountains cool down
faster than the valleys do because of their elevation. The
cool air sinks and flows down the mountain.

Sea breeze: The cool, high-pressure air over the ocean
that flows toward land

Land Breeze: the movement of air created by cool air
over land moving toward the ocean.
Sea Breeze
 During
the day, air over the ocean is cool.
Cool air masses form over areas of high
pressure. Air over the land is warmer, and
as it rises, it creates an area of low
pressure.

The cool, high pressure air over the ocean
now flows toward the land, creating a sea
breeze.
Sea Breeze
Land Breeze
 At
night, the air over the ocean is warmer
than the air over the land. (WHY?)
 The warm air over the ocean rises creating
an area of low pressure.

The cool air over the land forms an area of
high pressure and moves toward the ocean,
producing a land breeze.
Land Breeze
Mountain Breeze
 At
night, the mountains cool down faster
than the valleys do, because of their
elevation.
 The cool air SINKS and flows down the
mountain, causing a mountain breeze.
Mountains affect:
 Patterns

of Rainfall
Rain Shadow Effect
Wet
Side
Dry
Side
Which breeze am I?
Sea Breeze
Land Breeze
Mountain Breeze
Valley Breeze
Air Pressure and Barometers
 Temperature
affects air pressure.
 Lighter, warm air creates low air pressure
 Heavier, cold air creates high pressure.
 Barometers
measure air pressure.
 If air pressure changes, it means the
weather is probably going to change,
too.
Barometric Pressure
 Although
air feels as if it weighs
nothing it actually weighs a lot.
 Air pressure is the weight of the
air pressing against everything
on Earth.
 Barometers measure air
pressure.
Pictures of Barometers
Rising Barometric
Pressure
 If
the air pressure changes from
low to high pressure, the
barometric pressure is rising.
 The weather will probably be nice
and clear.
Falling Barometric
Pressure
 If
the barometric pressure
changes from high to low
pressure, it is falling.
 This means a storm might be
coming.
Other Weather Tools that help Predict the Weather
 Anemometer
measures wind speed.
 Thermometer
measures temperature
outside.
 Rain
fall.
Gauge measures the amount of rain
 Hygrometer
measures the amount of
humidity or moisture is in the air
 Wind
Vane: measures wind direction
Rain: Warm Air and Cold Air Meeting Forms
Rain
Cool air sinks and forms an area of high pressure.
Warm Air Rising Above a Cold
Front: Warm air rises and creates
an area of low pressure.
Jet Streams





Jet streams are narrow bands of fast moving air
about eight miles above the Earth's surface.
They are among the most powerful forces on the
planet. Jet streams affect surface weather.
Wind is the movement of air from a high
pressure area to a low pressure area.
Winds curve because of Earth's rotation.
In the temperate zone, warm and cold air clash
along weather fronts.
Jet Streams
Global Wind Patterns





As equatorial areas are heated most, the air above
them warms and rises as it becomes lighter than
the surrounding air, causing an area of low
pressure.
In cooler areas, the air sinks because it is heavier
and results in an area of high pressure. Winds will
blow as air is squashed out by the sinking cold air
and drawn in under the rising warm air.
Any difference in temperature like this will always
cause a difference in air pressure – and therefore
winds will blow.
A good expression to remember is that: “Winds
blow from high to low" (ie: from high pressure to
low pressure).
So if you know the temperature and pressure in
different areas, you will always be able to predict
the wind direction.
Coriolis Effect
 Winds
do not simply blow in straight lines
from north to south. Instead, they are bent
by the spinning of the Earth: To the right
north of the equator, and to the left in the
south.
 The Coriolis Effect bends every wind on
Earth, resulting in a distinct pattern of
winds around the world
Trade Winds and Westerly Winds
 Trade
Winds: Blow mainly from the east;
for example the steady winds blowing
towards the equator from the subtropics.
 These are known as trade winds because
they were used by sailing ships carrying
trading goods around the world.
 Westerly Winds is a wind systems
blowing from the west and moving the
winds to the east
The Doldrums
 The
Doldrums are an area of low pressure
occurring where the trade winds meet
along the equator. Winds here are usually
calm or very light and so ships would
avoid the area because they would only be
pushed along very slowly.
Wind Chill

Temperature is the main factor affecting
how warm or cold you are. However, wind
can also play an important role, making you
feel colder than you would otherwise be.
 This is because the wind causes your body
to lose heat faster.
 The higher the wind speed, the more heat
is lost from your body and you therefore
feel colder.
 The temperature your body feels as a result
of the wind is called the wind chill
temperature.
Cold Air
 Cold
air is heavier than warm air.
 Cold air puts more pressure on
the planet.
 A cold air area is called “high
pressure.”
Warm Air
 Warm
air is lighter than cold air.
 Warm air puts less pressure on
the planet.
 An area of warm air is called “low
pressure.”
Low Pressure- air circulation
Low Pressure – Storm caused by
rising warm, moist air
High Pressure – air circulation
High Pressure – Sunny
Why is bad weather usually associated with low
pressure and good weather with high pressure?

In an area of low pressure, air from neighboring areas (which
are of higher pressure) moves in. It has nowhere to go but up.
Upward movement of air causes condensation of water vapor,
leading to the development of cloud and rain. So, a low pressure
area usually associated with bad weather.

In contrast, in an area of high pressure, the air at low levels
spreads outward and air descends from aloft. Downward motion
warms up the air and is favorable for evaporation. Hence, a high
pressure area usually has fine and dry weather. Air descends in
high pressure area and rises in low pressure area.
Weather Symbols