1. Air Masses

2. Air masses are classified according to their source regions
Air masses are classified according to their source regions. The main types of air masses, are warm and dry continental tropical, warm and humid maritime topical, cold and dry continental polar, cold and humid maritime polar, and arctic. All five main types of air masses can be found in North America.
Air Masses

4. A Front is a boundary between two air masses of differing densities that stretch over large areas of earth’s surface
FRONTS

5. In a cold front, cold, dense air displaces warm air and forces the warm air up along a steep front. Thunderstorms and squall lines are associated with cold fronts.
Cold front symbol

6. In a warm front, advancing warm air displaces cold air
In a warm front, advancing warm air displaces cold air. A warm front is characterized by extensive cloudiness and precipitation.
Warm front symbol

7. Stationary Front symbol
Sometimes, two air masses meet and neither advances; this type of front is called a stationary front.
Stationary Front symbol

8. Sometimes, a cold air mass moves so rapidly that it overtakes a warm front. The advancing cold air wedges the warm air upward and the cold air mass collides with the other cold air mass separating “occluding” the warm air mass from the ground.
Occluded front Symbol