Air Masses and Fronts

AIR MASSES AND
FRONTS

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AIR MASSES AND FRONTS

•Air mass - very large volume of air

with similar temperature and
moisture content throughout.

•Changes in the weather are

caused by the movement and
interaction of air masses.

Multiple Select

Changes in weather are caused by the _______ and ________ of air masses.

• Height

• Density

• Movement

• Interaction

CLASSIFYING AIR MASSES

• TEMPERATURE

• MOISTURE

 The temperature and moisture content of an air mass is

determined by the area over which the air mass forms.

 The area where an

air mass forms is
called its source
region.

For example, the Gulf of Mexico is a
source region and air masses formed
there are warm and moist.

Multiple Select

Air masses are classified by two characteristics ...

Choose the correct two

• Location

• Temperature

• Moisture Content

• Size

Multiple Choice

The area over which an air mass forms is called it's

• Temperature latitude

• Moisture source

• Source region

• Region Source

CLASSIFYING AIR MASSES

 Air masses are named for their moisture

characteristics:
Continental (c) – dry air
Maritime (m) – moist air

AND

 Air masses are named for their temperature

characteristics:
Polar (P) – cold air
Tropical (T) – warm air
Equatorial (E)– warmest air
Arctic (A) and Antarctic (AA) – coldest air

Match

Match the name of the air mass with its symbol

• cT

• mP

• mA

• cE

Continental Tropical

Maritime Polar

Maritime Arctic

Continental Equatorial

• Continental Tropical

• Maritime Polar

• Maritime Arctic

• Continental Equatorial

commons.wikimedia.org

GLOBAL AIR MASSES

THE AIR MASSES THAT AFFECT
WEATHER IN NORTH AMERICA

Maritime Polar – mP
moist, cold air mass that forms over water
Continental Polar – cP
dry, cold air mass that forms over land
Maritime Tropical – mT
moist, warm air mass that forms over water
Continental Tropical – cT
dry, warm air mass that forms over land

frank.mtsu.edu

AIR MASSES THAT AFFECT WEATHER IN N. AMERICA

FRONTS

When air masses that formed in
different areas meet, and do not
mix, they form a boundary called
a front.

These air masses usually don’t mix
because of different
temperatures and densities.

cold

warm

Multiple Choice

The boundary where two air masses meet but do not mix is called a

• weather wall

• seam

• front

• mass meeting

COLD FRONT

• Cold fronts can

move quickly and
bring thunderstorms,
heavy rain or snow.

• These storms are

usually followed by
cooler, drier weather.

A cold front forms where cold air moves
under warm air (which is less dense), and
pushes the warm air up.

COLD
FRONT

WARM FRONT

• The warm air

gradually replaces
the cold air and
brings steady
rainfall.

• The rain is usually

followed by clear
and warm weather.

A warm front forms where warm
air moves over cold, denser air.

WARM
FRONT

OCCLUDED FRONT

• The coldest air mass

moves under and
pushes up the warm air
mass.

• The coldest air mass then moves

forward until it meets the cold air
mass that is less dense. It either
pushes this mass up as well, or
mixes with it.

• This front brings large

amounts of rain or snow
and cooler temperatures.

An occluded front forms when a warm
air mass is caught between two colder
air masses.

OCCLUDED

FRONT

STATIONARY FRONT

• The cold air mass

does not have
enough force to
push the warm air
mass above it.

• The two air masses

remain separated
and may cause
days of cloudy,
wet weather.

A stationary front forms when a cold
air mass meets a warm air mass.

STATIONARY

FRONT

No Movement

Multiple Choice

Which kind of front causes days of cloudy, wet weather?

• Cold

• Warm

• Occluded

• Stationary

Multiple Choice

Which kind of front brings thunderstorms, heavy rain or snow?

• Cold

• Warm

• Occluded

• Stationary

Multiple Choice

Which kind of front brings steady rain, followed by warmer, clear weather?

• Cold

• Warm

• Occluded

• Stationary

A

B

C

D

Match

Use the diagrams on the last slide to match the diagram to the correct front

• Stationary

• Cold

• Warm

• Occluded

D

A

B

C

• D

• A

• B

• C