Air Masses in North America Overview

Questions and Answers

What is an air mass?

An air mass is an immense body of air characterized by similar temperatures and amounts of moisture at any given altitude.

What happens as an air mass moves over an area?

The air mass changes the weather in the area over which it moves.

How are air masses classified?

Air masses are classified by temperature (polar or tropical) and the surface (continental or maritime) over which they form.

Which types of air masses have the greatest effect on weather in North America?

Continental polar and maritime tropical air masses. Signup and view all the answers

Why do continental tropical air masses have little effect on weather in North America?

Such air masses rarely move from their source regions. Signup and view all the answers

Compare and contrast the four types of air masses.

They are similar in that each influences weather in North America. They differ in that continental air masses form over land and thus are dry, while maritime air masses form over water and thus are wet. Polar air masses are cold, while tropical air masses are warm. Signup and view all the answers

Which type of air mass could offer relief from a scorching summer to the Midwestern United States? Justify your choice.

A continental polar (cP) air mass is cool and dry and is usually associated with high pressure and clear skies. Such an air mass would offer relief from hot summer weather. Signup and view all the answers

How can continental polar air be responsible for lake-effect snowstorms in the Great Lakes region?

Although cP air masses are cold and dry, they acquire moisture as they cross the relatively warm lakes. The addition of moisture and the increase in temperature make the air masses unstable, causing snow to fall downwind of the lakes. Signup and view all the answers

What kind of weather could be expected in southern Canada if an mT air mass was to invade the region in mid-July?

Oppressively hot and humid weather typical of the source region of the air mass would occur in southern Canada. Signup and view all the answers

Study Notes

Air Masses Overview

An air mass is a large body of air with consistent temperature and moisture levels at a particular altitude.

Effects of Air Mass Movement

As an air mass shifts over a region, it can alter the local weather patterns.

Classification of Air Masses

Air masses are categorized based on temperature (polar or tropical) and their formation surface (continental or maritime).

Key Air Masses in North America

Continental polar (cP) and maritime tropical (mT) air masses significantly influence North American weather.

Continental Tropical Air Masses

Continental tropical (cT) air masses have minimal impact on North American weather due to their infrequent movement from source regions.

Comparison of Air Mass Types

All four air mass types affect North American weather.
Continental air masses: dry, form over land.
Maritime air masses: wet, form over water.
Polar air masses: cold; tropical air masses: warm.

Weather Relief from Continental Polar Air Mass

A continental polar (cP) air mass can provide cool, dry air to relieve excessive summer heat in the Midwest, typically linked to high pressure and clear skies.

Lake-Effect Snowstorms

cP air masses can generate lake-effect snow in the Great Lakes region by gaining moisture from warm lakes, leading to unstable air and subsequent snow downwind.

Weather Conditions from mT Air Mass

If a maritime tropical (mT) air mass encroaches upon southern Canada in mid-July, extremely hot and humid conditions characteristic of its source area are expected.

Description

Explore the characteristics and classifications of air masses that significantly affect weather patterns in North America. Learn about the differences between continental and maritime air masses, as well as polar and tropical types. This quiz covers the fundamental concepts needed to understand air mass dynamics and their impact on local weather.