| A | B |
|---|
| air mass | a large body of air where TEMPERATURE and MOISTURE CONTENT are constant throughout |
| maritime (m) | the air mass that forms over water and is wet |
| continental (c) | the air mass that forms over land and is dry |
| polar (P) | the air mass that forms over the polar regions and is cold |
| tropical (T) | the air mass that forms over the Tropics and is warm |
| source region | where an air mass forms |
| cold front | cold air moves under warm air; moves quickly and brings thunderstorms, heavy rains and snow. Colder weather follows. |
| warm front | warm air moves over cold air; moves slowly and brings drizzly rain. Warm weather follows. |
| occluded front | warm air mass caught between two cold air fronts; brings large amounts of rain and snow. Cooler temperatures follow. |
| stationary front | a cold air mass meets a warm air mass; they each stay still and cause many days of cloudy, wet weather |
| cyclone | low pressure in the middle;winds spiral inward; brings stormy weather |
| anticyclone | high pressure in the middle; winds spiral outward; brings dry, clear weather |
| front | the boundary between air masses of different densities and usually different temperatures |
