Air Masses

Air Mass is an extremely hot body of air whose temperature and humidity are relatively the same throughout. Source Regions, where the air mass comes from, are generally light, flat winds, found in high pressure areas. Source Regions are what classifies an Air Mass.

• A=Arctic
• E=Equatorial
• P=Poles
• T=Tropic
• c=continental (air is dry because it forms over land)
  
• m=maritime (air is moist because it forms over water)

**Note: Code letters are combined to specify Source Regions**

Air Mass formation: If surface air resides in a region for a few days it acquires thermal and moisture characteristics of the underlying surface. Because it generally takes a few days to form,, ares take shape of high pressures with light winds. Air masses can change as it passes over ares with differing surface characteristics, if this happens, it will change the characteristics of the air mass.


**us code letter above to refer to if necessary:

P=

A or AA
Extremely cold and dry air forming from over the poles.

cP
Contains cold and dry air forming from over sub polar regions. Causes bitterly cold winters, and pleasant summers.

mP
Contains cold and moist air, and may bring along little rain



T=

cT
Warm, dry air; often over southwest US and mexico in the summer, produces temperatures above 100F.

mT Warm moist air originating from the Atlantic ocean, Caribbean Sea, or Gulf of Mexico.



EQUATORIAL
E= almost never reaches Canada, and rarely continental US. Brings extremely hot and humid air, most of equatorial land is covered in humid tropical rain forests.





More on air temperatures and air mass movement
Wikipedia Air Mass