Download and maritime tropical (mT) air masses. Weather in North

Air Masses & Weather
• 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.
Tornado Damage
The force of wind during a tornado in Kansas was
strong enough to drive this metal into a utility pole!
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
Good
Good
Good
Good
Good
Good
Good
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.
Weather in North America
• Continental Polar Air Masses
– (cP): cool/dry
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.
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.
Formation of a Maritime Polar
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, droughtlike conditions in the Great Plains.
– In the fall - mild weather in the Great Lakes
region, often called Indian summer.
Quick Review!
1. 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?