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Air Masses and Fronts
Air masses take on the characteristics of the area where they form.
Air masses are classified according to their temperature and moisture content

Warm air forms over tropical regions near the equator.
T- Tropical

Cold air forms over polar regions.
P- Polar

Wet air masses form over water
m- maritime

Dry air masses from over land.
c- continental
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 Moisture content is noted by the first letter.
m – maritime – wet
c – continental – dry
 Temperature is noted by the second letter.
P – polar – cool
T – tropical - warm
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What are the four types of air masses?




Maritime Tropical (mT)
Maritime Polar (mP)
Continental Tropical (cT)
Continental Polar (cP)
How do air masses move?


The prevailing westerlies are
the major wind belts in the
United States.
Prevailing westerlies push air
masses from west to east.
Fronts
 A front is a boundary
between two air masses of
different density, moisture,
and temperature, the collision
often causes storms and
weather changes.
 A front may be 15 to 200
kilometers wide and extend
as much as 10 kilometers up
to the troposphere.
 The kind of front that
develops depends on the
characteristics of the air
masses and how they move.
There are four types of fronts.
 Cold Fronts.
 Warm Fronts.
 Stationary Fronts.
 Occluded Fronts.
Cold Fronts

Cold air mass meets a warm
air mass and pushes the warm
air mass out of its way.

Bring thunderstorms, rain or
snow.

Most tornadoes develop from
thunderstorms on the edge of
a cold front.

Cold fronts are followed by
cooler drier air.
Warm Fronts

Warm air mass meets a
cold air mass and
pushes the cold air
mass out of the way.

Brings drizzly
precipitation.

Followed by clear warm
weather.
Stationary Fronts

Cold air meets warm air.

Not enough force to move
either front.

Many days of cloudy, wet
weather.
Occluded Fronts

Warm air caught between
two cold air masses.

Brings cool temperatures
with large amounts of rain
or snow.
Cold Front, Warm Front, Stationary
Front and Occluded Front Animation
http://www.stevemcentee.com/animation3.html
Click on the link above.

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Section Review Questions
Answer the following questions on the paper provided.
1. Describe a maritime polar (mP) air mass, in terms of moisture and
temperature.
2. What is the name of an air mass that forms over water?
3. What is the name of an air mass that forms over land?
4. What is the name of an air mass that forms in a cold region?
5. What is the name of an air mass that forms in a warm region?
6. Describe a continental tropical (cT) air mass, Moisture and temperature.
7. The boundary between two air masses is called a
______________________.
8. A cold air mass meets and pushes a warm air mass out of the way.
What type of front am I?
9. A warm air mass is trapped between to cold air masses.
What type of front am I?
10. A warm air mass meets and pushes a cold air mass out of the way.
What type of front am I?
11. I am a front that brings drizzly rain and am followed by warm clear
weather. Name me
12. A cold air mass meets a warm air but neither is very strong. They are
separated and many days of wet , cloudy weather occur.
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