Download Fronts

What
do you think
happens when two
air masses meet?
Why?
What is a front?
http://www.natgeoeducationvideo.com/film/1193/t
he-movement-of-air-masses
 When
two air masses meet, the air
within them does not easily mix.
 the air stays within its own air mass.
 Because
of this a border forms
between two clashing air masses,
as they rub together.
 This border is called a front.
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Each air mass has a different
temperature depending on its’
geographic origin.
Fronts are caused by winds moving one
air mass away from its geographical
origin (birthplace).
Fronts are usually associated with rain,
snow, or hail. Thunderstorms, tornados
and other severe weather can occur with
fronts.
There are 4 different types of fronts:
Cold Front
Warm Front
Stationary Front
Occluded Front
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A front bringing in a cold air mass is referred to as
a cold front.
Cold air is dense and tends to sink.
Typically cold fronts move faster.
The combination of higher speed, and slope push
warm air masses upward very quickly.
Cold Fronts are usually associated with more violent
weather.
After a cold front passes through, weather is usually
clear and cool.
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Fronts that bring warm air are referred to as
warm fronts.
Warm fronts move slowly.
Cold air is more dense than warm air, so the
warm air moves over the cold air. As the air in
the warm air mass rises, it expands, causing it
to cool down.
As it cools, water vapor can condense creating
precipitation and clouds/fog.
After a warm front passes through the weather
is usually warm and humid.
Winter warm fronts bring snow
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When two air masses come together, but
neither one is strong enough to move the
other, the boundary between them is referred
to as a stationary front. (like a stand-off)
Where the warm and cold air meet, water
vapor in the warm air turns into rain, snow,
fog, or clouds.
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A warm air mass becomes “trapped” between two
cold fronts.
The denser cold air moves underneath the warm air
and pushes it up.
The warm air above the cool air allows for water
vapor to condense and turn cloudy, rainy, or
snowy.
http://www.youtube.com/wat
ch?v=tkK4_F0VKhM