1. FRONTS

2. What are Fronts?
An interface (boundary) between 2 air masses. Where 2 different air masses meet.
Conditions at the front are unstable and usually associated with precipitation

3. Types of Fronts: Page 13 in E.S.R.T.
Icicles
Half Suns

4. Cold Fronts: Cold air moves into an area occupied by warm air
Warm air is already in place.

5. The colder, denser air quickly pushes against and under the warm air
The warm air rises, producing tall, thick clouds 5

6. Wind speed increases, air pressure drops
Precipitation occurs – moves quickly and violently 6

7. Cumulonimbus Cloud forms7

8. Cold Fronts:
Temperatures are cooler behind a cold front, and warmer ahead of the cold front.

9. Cold Front Animation

10. Warm Fronts:
Warm air mass moves into an area occupied by cool air

11. Warm air slides over the cold air.

12. The warmer, less dense air slowly moves over cold air mass
Warm air slowly rises, expands, cools, and clouds form 12

13. 13

14. Air pressure falls, and precipitation follows
Lasts for a longer period of time 14

15. Warm Fronts:
Temperatures are warmer behind a warm front, and cooler ahead of the front.

16. Warm Front Animation

17. Stationary Fronts:
A cold air mass and a warm air mass collide, with no movement

18. Widespread rain will last for many days

19. Stationary Front Animation

20. Occluded Front:
Faster moving cold front overtakes a slower moving warm front

21. Warm air gets caught in between 2 cold air masses
Widespread rain and thunderstorms 21

26. Precipitation occurs right along the frontal boundary