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Air Masses
Air Masses
 Weather changes when new air masses
move into the area.
 An AIR MASS is a large volume of air in
which temperature and humidity are nearly
the same.
Formation
 They form when air sits over a large area for
many days.
 The air takes on the characteristics of the
land or water below.
 They can cover thousands of square miles.
Movement
 As air masses move they bring their
characteristics along with it
Review
 What is an air mass?
How can weather change with the arrival of a new
air mass?
Characteristics
 The characteristics of an air mass depend
upon where they come from.
 Every air mass has two names.
– One for moisture
– One for temperature
Moisture
 The first word to describe an air mass tells
where it was formed (how much water it
contains).
 Maritime (wet) – form over water.
 Continental (dry) – form over land
Temperature
 The second word describes the temperature
or where it began.
 Tropical (warm)– form closer to the equator.
 Polar (cold) – form closer to the poles.
Examples
 Continental Tropical: dry and warm
 Continental Polar: dry and cold
 Maritime Tropical: wet and warm
 Maritime Polar: wet and cold
Review
 What does each word of the air mass’s
name represent?
Explain the Air Masses
Air Masses
Real World Uses
 Meteorologists use abbreviations for the
words.
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
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Continental is written as “c”
Maritime is written as “m”
Tropical is written as “T”
Polar is written as “P”
Practice
 Assign a name to the following
– A wet, cold air mass
– A dry, warm air mass
– A dry, cold air mass
– A wet, warm air mass
How do air masses move?
 Global winds move air masses.
 Generally move west to east in the U.S.
 As the air mass moves, so does its
characteristics.