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Wild about
Weather
Weather is the current atmospheric conditions, such as air
temperature, wind speed, wind direction, cloud cover,
precipitation, relative humidity, air pressure, etc.
8.10B: global patterns of atmospheric movement influence local weather using
maps that show high, low pressures and fronts
8.10C identify the role of oceans in the formation of weather systems such as
hurricanes
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Change the way you think
• In order to understand weather, you need
to start thinking vertically!
• For example – air moving parallel to the
ground is called wind, while air moving up
and down is called a current
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Change the way you think
• Heated air rises, while cooler air sinks (the
same with water)
• The motion of air in the atmosphere above
our heads (vertically) plays a large part in the
weather we experience here at earth’s
surface.
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Climate vs. Weather
• Weather is daily changes in the
atmosphere, which includes temperature,
wind, humidity, etc.
• The average weather in an area is the
climate for that area
• For example: The weather in Austin Texas
on June 5th is 950 and warm, but the
climate for the area during summer is hot
and dry
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Oceans and Climate
How does the ocean affect our climate?
• The ocean is an important factor in global
climate because it collects and moves water,
heat and carbon dioxide.
– These components are constantly exchanged
between the atmosphere and the hydrosphere (water
on earth)
– Ex. water is evaporated from the hydrosphere to the
atmosphere
• The oceans can store a lot of heat. When the
ocean waters are warm, so is the air above it.
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Weather Patterns – why all of this happens…
Changes in the weather patterns occur as the earth tries to equalize the temperature. The equalization comes from
• Global Wind Currents
• Global Ocean Currents
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•An air mass is a large
body of air that has
similar temperature
and moisture
properties
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There are two ways to identify air masses. You can identify air masses by the amount of : moisture and temperature they have
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Using Moisture to identify air masses:
–Continental (c) -Located over large land masses - DRY
–Maritime (m) -Located over the oceans - HUMID
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Using temperature to
identify air masses:
–Polar (P) - Cooler
–Tropical (T) - Warmer
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Moisture and temperature are then combined to describe the air mass
–cT –
– cP –
– mT –
– mP –
Dry cold
Dry warm
Humid warm
Humid cold
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Put together on a map:
30o Latitude
Tropic of
Capricorn
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Fronts• A front is the front edge of
the boundary between air masses that have different characteristics.
• There are 4 different types of fronts
– Cold Front
– Warm Front
– Stationary Front
– Occluded Front
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Cold Front• The cold dense air behind a cold front
pushes the warmer air up forming
cumulus clouds
• A cold front usually moves fast and
causes showers and thunderstorms
• The weather after the front is colder
but dry and sunny
Add to your page!
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Warm Front• The warm air behind a warm front pushes over
the cooler air ahead of it forming stratus clouds
• A warm front causes steady rain, drizzle and fog. The clouds are slow to build, and the rain lasts longer
• After the front passes, the temperatures rise and it is more humid.
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Stationary Front
• A stationary front occurs when a
cold front and a warm front meet
up, but neither moves out of the
way
• The air is unsteady and sometimes
causes rain, and showers
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Stationary Front – Going Nowhere
• As the name implies, a stationary front doesn’t
move (for a while).
• If the stationary front produces rain, then the rain
continues to fall until the front does finally move.
• This type of front can lead to flooding (just as we
saw a few summers ago).
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Occluded Front• An occluded front occurs when two cooler
air masses merge, forcing warmer air to rise between them
• An occluded front usually brings dry air. Weather similar to a warm front
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What are “pressure systems”?
• Again, think “vertically.”
• Basically, air cools as it rises, which can cause
water vapor in the air to condense into liquid
water droplets, sometimes forming clouds and
precipitation.
• On the other hand, sinking air is associated
with warming and drying conditions.
• So the first important point to keep in mind is
rising air = moistening, sinking air = drying.
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Pressure SystemsDraw these in your notes!
Leave room underneath these two to add information!
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Pressure Systems - High
• Higher density air sinks
• Pressure gets higher
• Winds go clockwise
(draw arrows in your
box)
• Good weather
• Few clouds, no rain
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Pressure Systems - Low
• Low density air rises, then
cools.
• When it cools, water vapor
condenses and forms
clouds
• Winds go counter-
clockwise
• means stormy weather,
clouds and rain
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Online Weather Exploration