| A | B |
|---|
| tropical | warm air masses with low pressure |
| polar | cold air masses with high air pressure |
| maritime | air masses that form over oceans |
| continental | air masses that form over land |
| front | area where air masses meet but do not mix |
| cold front | forms when cold air moves underneath warm air, forcing the warm air to rise |
| warm front | forms when warm air moves over cold air |
| stationary front | a cold and warm air mass meet, but neither has strength to move the other out |
| occluded front | two cold air masses meet and force the warm air up |
| cyclone | counterclockwise swirling center of low air pressure |
| anticyclone | clockwise swirling high pressure systems of dry air |
