| A | B |
|---|
| air mass | a large body of water that has properties similar to the part of Earth's surface over which it develops |
| front | a boundary between two air masses of different density, moisture or temperature. |
| cold front | when colder air advances toward warm air. The cold air wedges under the warm air like a plow or a bulldozer. Warm air is lifted, cools and condenses. Produces thunderstorms and even tornadoes. |
| Warm front | lighter, warmer air advances (slides) over heaver, colder air. Produces hours or days of wet weather. |
| Occluded front | 3 air masses of different temperatures. Colder air forces warm air up and closes off warm air from the surface |
| Stationary | occurs when a boundary between air masses stops advancing. May remain in same place for several days producing light wind and precipitation. |
| 4 | the number of fronts |
| high pressure | associated with fair weather |
| low pressure | associated with cloudy weather |
| barometer | measures atmospheric pressure |
