1. Air Masses and Fronts

2. Air mass – large bodies of air that have uniform temperature, humidity and pressure Air masses are classified by temperature and moisture – those formed over water are called maritime, those formed over land are called continental; warm masses are tropical and cold are polar

3. What are the four types of air masses?
Maritime Tropical
Maritime Polar
Continental Tropical
Continental Polar

5. How do air masses move? Air masses move with help from global winds.
Tradewinds
Polar easterlies
Prevailing westerlies

7. In the continental United States, air masses are commonly moved by prevailing westerlies and jet streams.

8. Fronts
When air masses meet there is a front, the collision often causes storms and weather changes.
A front may be 15 to 200 kilometers wide and extend as much as 10 kilometers up to the troposphere.
The kind of front that develops depends on the characteristics of the air masses and how they move.

9. There are four types of fronts.
Cold Fronts.
Warm Fronts.
Stationary Fronts.
Occluded Fronts.

10. Colliding air masses can form four types of fronts:
cold fronts – cold air moves under warm air forcing warm air up
warm front – move slowly and bring warm, humid air
stationary front – forms when a cold mass meets a warm mass but neither have enough force to move the other
occluded front – warm air mass is caught between two cold air masses