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 pushes against and under the warm air
The warm, less dense air rises, producing thick, tall clouds
Wind speed increases, air pressure drops
Precipitation occurs – moves quickly and violently

6. Temperatures are cooler behind a cold front, and warmer ahead of the cold front.

7. Cold Front Animation

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

9. Warm air slides over the cold air.

10. The warmer, less dense air moves on top of cold air mass
Warm air rises, expands, cools, and clouds form
Air pressure falls, and precipitation follows
Lasts for a longer period of time

11. Temperatures are warmer behind a warm front, and cooler ahead of the front.

12. Warm Front Animation

13. Warm Front Animation

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

16. Widespread rain will last for many days

17. Stationary Front Animation

18. A collision of air masses – warm and cold fronts meet

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

20. Warm front gets caught in between 2 cold fronts
Widespread rain and thunderstorms
Warm front gets caught in between 2 cold fronts
Widespread rain and thunderstorms

21. Precipitation occurs right along the frontal boundary

22. Counter-clockwise What direction is this low pressure system rotating?
On a weather map, fronts attach at a low pressure. Knowing this we can predict where each of the fronts will be next.
What direction is this low pressure system rotating?
Counter-clockwise

23. Front Questions Q: Towards what direction is the cold front moving?
A: South East
Q: Towards what direction is the warm front moving?
A: North

24. Front Questions: Q: Is it colder in Los Angeles or El Paso?
A: Los Angeles
Q: Is it warmer in Memphis or New York?
A: Memphis
Q: What cities have high pressure?
A: Houston, Seattle
Q: What cities might be experiencing rain?
A: El Paso, Memphis