1. Weather & Storms

2. Air Masses & Weather Air Masses Movement of Air Masses
A large body of air with the same temperature and amount of moisture at any altitude
Movement of Air Masses
As it moves, the characteristics of an air mass change and so does the weather in the area over which the air mass moves.

3. Tornado Damage The force of wind during a tornado in Kansas was strong enough to drive this metal into a utility pole!

4. Classifying Air Masses
Air masses are classified according to the surface over which they form
Term
Abbreviation
Air will be…
Maritime (Ocean) m
Moist
Continental (Land) c
Dry
Polar (Poles) P
Cold
Tropical (Equator) T
Warm

5. Good
Good
Good
Good
Good
Good
Good

6. Weather in North America
Much of the weather in North America, especially weather east of the Rocky Mountains, is influenced by continental polar (cP) and maritime tropical (mT) air masses.

7. Weather in North America
Continental Polar Air Masses
(cP): cool/dry

8. Weather in North America
Maritime Tropical Air Masses
mT: warm/wet
Warm, loaded with moisture, and usually unstable.
The source most precipitation received in the eastern two-thirds of the United States.

9. Weather in North America
Maritime Polar Air Masses
(mP): wet/cool
Begin as cP air masses in Siberia. The cold, dry air changes into mild, humid, unstable air during its long journey across the North Pacific.
They also originate in the North Atlantic off the coast of eastern Canada.

10. Formation of a Maritime Polar

11. Weather in North America
Continental Tropical Air Masses
(cT): dry/warm
Only occasionally do cT air masses affect the weather outside their source regions.
In the summer - extremely hot, drought-like conditions in the Great Plains.
In the fall - mild weather in the Great Lakes region, often called Indian summer.

12. Quick Review!
What kind of air would you expect to find in a mT air mass?
2. Which two air masses influence MOST of our weather in North America?
3. List the TWO defining features of an air mass?