1. Weather Systems

2. Coriolis Effect
Imagine how the atmosphere acts as the Earth rotates on its axis. It is NOT attached to Earth’s surface!
Coriolis effect
Coriolis Effect

3. Coriolis effect
The Coriolis effect is the apparent deflection of a body in motion with respect to the Earth, as seen by an observer on Earth.
It is caused by the rotation of the earth

4. Coriolis Effect NASA – Coriolis Effect on Astronauts
Plane travel – Coriolis Effect on Air Travel

5. Global Wind Systems
Three basic zones, or wind systems in each hemisphere
Remember that winds are named for the direction that they blow FROM, not TO

7. Trade Winds Trade Wind air moves toward the equator
Warm, steady, continuous breezes
Appear to be curving to the west. Why?

8. Doldrums The doldrums are an area of calm weather
The trade winds meet near the equator
Produce upward winds as they are heated, so there are no steady surface winds. 

9. Prevailing Westerlies
The prevailing westerlies are between 30 and 60 latitude
Winds are named from the direction that they blow from.
In Northern Hemisphere - responsible for movement of weather west to east across US and Canada

10. Polar Easterlies
Polar easterlies are found between 60 latitude and the poles
Consist of cold air

11. Jet Streams
Jet streams are narrow bands of fast, high-altitude westerly winds
Most significant - polar jet stream

12. 4 Types of weather fronts:
Cold Front
Warm Front
Stationary Front
Occluded Front

13. Cold front
The direction that the teeth point indicate the direction the front is moving.

14. Cold Front

15. What is happening?
Fast moving cold air mass slow moving warm air mass
Cold air slides under the lighter warmer air.
The weatherman says…
Clouds, showers, and sometimes thunderstorms associated with cold fronts

16. Warm Front

17. Warm Front

18. Faster moving warm air mass takes over the slowly moving cold air mass
Warm air moves over the cold air.
And the weather man says…
Associated with cloudiness and precipitation

19. Stationary Front

20. Stationary Front

21. Cold air mass and warm air mass meet.
Neither air mass has enough force to move the other air mass out of the way.

22. Occluded front

23. Occluded Front

24. Warm air mass is caught between two cooler air masses
Cold air masses move underneath the warm air mass and push it upward.
The weatherman says…
Precipitation is common on both sides of an occluded front.

25. Which types of fronts can you find?

27. High vs Low Pressure Systems
Rising and sinking air results in rotation
High-pressure system:
Air sinks and spreads away from the center
Rotates clockwise direction in N hemisphere
(counterclockwise in S hemisphere)
Low-pressure system:
Air rises and moves counterclockwise N hemisphere
(clockwise S hemisphere)

30. High VS Low Pressure Systems
High pressure systems - fair weather
Low pressure systems - clouds and precipitation

31. map showing isobars, lines of equal pressure.