Air Mass Classification

  • four general categories according to source region (see table)

  • extremely cold cP air is sometimes denoted at cA

  • extremely hot, humid mT air is sometime denoted by mE

Air Masses on the move:

  • if an air mass is colder than the surface over which it is moving, "k" is added

  • if an air mass is warmer than the surface over which it is moving, "w" is added

Example - a cP air mass moving over the great lakes in December becomes cPk

Source Region

Polar

Tropical
Land - continental (c) cP (cold, dry, stable) cT (hot, dry, stable air aloft; unstable surface air
Water - maritime (m) mP (cool, moist, unstable) mT (warm, moist; usually unstable)