1. Weather
Notes

2. “The only thing predictable about life is that it is unpredictable
“The only thing predictable about life is that it is unpredictable.” -Remy Ratatouille

3. What is an air mass?
An air mass is a huge body of air with
uniform temperature, pressure, and
humidity (moisture).

4. There are four types of air masses
which combine to create the different
climates of the United States.

5. Tropical: warm air coming from the
tropics, with low pressure.

6. Polar: cold air coming from the poles,
with high pressure.

7. Maritime: moist, humid air coming
from over the ocean.

8. Continental: dry air coming from
inland regions.

9. See how the different combinations of
air masses give areas their typical
weather type?

10. Maritime Tropical air masses are
what makes the South so warm and
humid!

11. Maritime Polar air masses are what
makes Seattle so cold and rainy!

12. Continental Tropical air masses are
what makes the Southwest so hot and
dry!

13. Continental Polar air masses are what
make the northern states and Canada
so bitterly cold!

14. In America, the Prevailing Westerlies keep most air masses moving from
West to East.
They turn because of the spinning of the Earth. This is called Coriolis Effect (reasons for Prevailing Westerlies and reason why Earth spins)

15. What happens when two air masses
run into each other?
a FRONT occurs when two air masses collide (like a battle front)

16. There are four types of fronts, all of
which tend to cause clouds and rain.
The type of front depends on the air
masses and their speed. The faster
moving air mass always wins the front!

17. Cold Front: fast moving cold air mass
meets slow moving warm air mass.
The warm air gets pushed up out of the
way, so the cold air stays underneath.

18. Cold fronts usually cause sudden
weather changes and storms.
Affects: After the cold front passes,
it is clear and colder out.

19. Warm Front: fast moving warm air
mass meets slow moving cold air mass.
The faster moving warm air pushes
the cold out of the way!

20. Warm fronts causes slow forming storms that stay longer.
Affects:After the warm front passes,
it is warmer and humid air.

21. Stationary Front: Both cold and warm air masses are moving slowly.
Cause: Neither air mass is moving fast enough to push the other out of the way.

22. The Affects: the front gets stalled
and brings many days of rain, fog,
clouds, or snow.

23. Occluded Front: When a warm air
mass gets caught between two cold
air masses.
(Occluded means blocked)

24. Affects: Occluded fronts can bring clouds, rain, and even snow.

25. The two factors that affect the
weather the MOST are:
1) Temperature
2) Altitude

26. There are two main factors that
decide what air pressure we feel.
#1 = Altitude: how high up in the
atmosphere you are.

27. Oxygen is heavier than Nitrogen, so
it sinks to the bottom of the atmosphere.
That means that the lower you are, the more weight is pushing on your head!

28. This means: the less oxygen there will be
to breathe the higher you are!
(This is why people take oxygen tanks
when climbing Mt. Everest)

29. #2 = Temperature: When it is cold, the
oxygen will huddle together, putting
even more molecules on your head!
Cold
Hot
High Pressure
Low Pressure

30. High Pressure (cold) Low Pressure (warm)
To equalize the amount of pressure,
oxygen will move to evenly distribute it.
High Pressure (cold)
Low Pressure (warm)
We can see and feel the oxygen moving...

31. Air moving from an area of high
pressure to an area of low pressure
is WIND!

32. With temperature, pressure, and wind
comes all sorts of crazy weather....
floods
winter storms
thunderstorms
hurricanes
tornado