8.3 Air Masses and Fronts

Air Masses and Fronts

What is Air Mass?

●Air Mass is a huge body of air that has similar temperature, humidity, and
air pressure at any given height

Types of Air Mass

●There are FOUR major types of air masses that influence the weather in
North America:

○Maritime tropical

○Continental tropical

○Maritime polar

○Continental polar

Multiple Choice

Which is NOT a type of Air Mass?

• Maritime Tropical

• Maritime Polar

• Continental Polar

• Continental Drift

Types of Air Mass

●The characteristics of an air mass depend on the temperatures and
moisture continent of the region over which the air mass forms

●Temperature directly affects air pressure

●Cold, dense air has a higher pressure while warm, less dense air has lower
pressure

Multiple Choice

Cold, dense air has ___________________ pressure

• High

• Low

Multiple Choice

Warm, less dense air has ________________ pressure

• Low

• High

Types of Air Mass

●Tropical means warm air masses that form in the tropics and have low
pressure

●Polar means cold air masses that form north of the 50 degree north
latitude and south of the 50 degree south latitude

Types of Air Masses

●Maritime means air masses that form over oceans

●Continental means air masses that form over land

Multiple Choice

Maritime means _________________

• warm air masses formed in the tropics

• cold air masses formed near the north and south pole

• air masses that form over oceans

• air masses that form over land

Maritime Tropical

Maritime Tropical air mass is when
warm humid air masses form over
tropical oceans

They form over the Gulf of Mexico and
the Atlantic Ocean

Fill in the Blank

Maritime Tropical is when warm, humid air mass forms over _____________________

Maritime Tropical

The air masses move north and northeast and affect the
weather in the central and eastern United States

In the west, maritime tropical air masses form over the
Pacific Ocean

They affect weather on the West Coast and when they
cross mountain ranges, they lose moisture

Multiple Choice

When Maritime Tropical air masses cross mountains they _________________

• Gain Moisture

• Gain humidity

• Lose Moisture

• Lose Humidity

Maritime Tropical

In the summer, maritime tropical air masses usually bring hot,
humid weather

Many summer showers and thunderstorms in the eastern
United States develop in air masses that have formed over the
Gulf of Mexico

In the winter the humid air mass can bring heavy rain or snow

Maritime Polar

Maritime Polar means cool, humid air masses
that form over the icy cold North Pacific and
North Atlantic oceans

Maritime polar air masses affect the West Coast
more than the East Coast

Even in the summer, these masses of cool, humid
air often bring fog, rain, and cool temperatures to
the West Coast

Fill in the Blank

Maritime Polar air masses form over the ___________ oceans

Multiple Choice

In the Summer, Maritime Polar air masses bring fog, rain, and cool temperatures to ______________

• The East Coast

• The West Coast

• The Great Plains

• The Midwest

Continental Tropical

Continental Tropical means hot, dry air masses
that form mostly in summer over dry areas of the
Southwest and northern Mexico

Continental Tropical air masses cover a smaller
area than other air masses

They occasionally move northeast, bringing hot,
dry weather to the southern Great Plains

Multiple Choice

Continental Tropical brings dry and hot weather primarily to ___________

• The Southwest and Mexico

• The Northwest

• The East Coast

• The whole United States

Continental Polar

Continental Polar means a large mass
forms over central and northern Canada
and Alaska

Air masses that form near the Arctic Circle
can bring cold weather with very low
humidity.

Multiple Choice

Air Masses that form near the Arctic Circle can bring _______________

• Hot weather and low humidity

• Hot weather and high humidity

• Cold weather and low humidity

• Cold weather and high humidity

Continental Polar

In winter, continental polar air masses bring
clear, cold, dry air to much of North America

In summer, the air mass is milder.

Storms may occur when continental polar air
masses move south and collide with maritime
tropical air masses moving north

Fill in the Blank

Storms may occur when continental polar air masses move south and collide with ________________ air masses moving north