1. Air Mass and Fronts

2. What is an Air Mass?
A large body of air that has similar temperature and moisture throughout
Usually cover thousands of square kilometers
They are classified by where they form

3. What are the 4 types of air mass?
Maritime: forms over water; wet
Polar: forms over the polar regions; cold
Continental: forms over land; dry
Tropical: develops over the tropics; warm
What are the 4 types of air mass?

4. What are the air masses that affect the weather in the U.S.?
Maritime Tropical: forms over the ocean near the equator; holds warm, moist air. In the summer, it brings hot, humid weather but in the winter, if it comes in contact with a cold air mass, rain and snow will fall

5. Maritime Polar: forms over the Pacific Ocean in both winter and summer
Maritime Polar: forms over the Pacific Ocean in both winter and summer. It forms over the cold North Atlantic Ocean in the summer. In the summer, it brings cooler temperatures to the eastern U.S. and fog to the western states. Heavy snow and cold temperatures are produced in the winter.

6. Continental Tropical: forms over land in Mexico during the summer
Continental Tropical: forms over land in Mexico during the summer. It brings dry, hot air to the SW states. It also forms over land in northern Canada. In winter, this cold, dry air mass causes extremely cold temperatures in the U.S.

7. Continental Polar: develops over land in northern Canada
Continental Polar: develops over land in northern Canada. In the winter, this air brings extremely cold weather to the U.S. In the summer, it generally brings cool, dry weather.

8. When two air masses that do NOT have the same properties meet and they do not mix. Instead, a boundary forms that is called a front.
The weather at a front is usually stormy and unsettled
Named after whichever air mass is the “attacker”.
What is a front?

9. What are the 4 types of fronts?
Cold Front: forms when a cold air mass meets and pushes under a warm air mass. The cold air mass forces its way underneath the warm air mass and pushes it upward. Violent weather is associated with a cold front and then fair, cool weather follows. Travels faster than warm fronts.

10. Warm Front: forms when a mass of warm air overtakes a cold air mass and moves over it. Light rain and showers usually accompany it and then hot, humid weather follows.

11. Occluded Front: when a cold front overtakes a warm front
Occluded Front: when a cold front overtakes a warm front. As the warm air is pushed upward, the cold air meets cool air. It may also form when cool air overtakes a cold front and warm air is pushed upward. Produces less extreme weather than a cold front or a warm front. Usually cool temperatures and large amounts of precipitation.

12. Stationary Front: formed when a warm air mass meets a cold air mass and no movement occurs. Rain may fall in an area for many days. Weather produced is similar to a warm front.

14. Review Video

15. Vocabulary Air Mass – Cold Front - Warm Front – Stationary Front –
Occluded Front –
Jet Stream -