| A | B |
| thermosphere | The upper layer of the atmosphere where temperatures are extremely high. |
| mesosphere | The layer of atmosphere where air is thin and most meteors burn up. |
| stratoshpere | The layer of the atmosphere in which ozone is present. |
| troposhpere | The bottom layer of the Earth's atmosphere. |
| air mass | A large body of air that has the same characteristics throughout. |
| air pressure | The weight of air pressing down on an area. |
| relative humidity | A comparison of the actual amount of moisture that could be in the air at the same temperature and pressure. |
| front | The border between two air masses that collide. |
| warm front | When a warm air mass moves into an area of cooler air. |
| cold front | When a cold air mass moves into an area of warmer air |
| cirrus clouds | igh clouds that signal a warm front is comeing |
| cumulonimbus clouds | Towering clouds that that bring heavy precipitation when a cold front occurs. |
| stationary front | When the boundary between two air masses don't move. |
| occluded front | When a cold front overtakes a warm front. |
| forecast | a prediction of what the weather will be like in the future |
| station model | An arrangement of symbols and numbers that show the weather conditions recorded at a weather station. |
| surface map | This has station models and information about fronts and about centers of high pressure and low pressure. |
| weather balloon | Carries a package of instruments that records data about temperature, air pressure and humidity. |
| weather map | Shows data about recent weather conditions across a large areas. |
| thunderstorm | A very strong storm with a lot of rain, thunder and lightening. |
| hurricane | Large spiarling storm systems that can be as much as 600 km across. |
| tropical storm | When winds of a tropical depression reach a constant speed of 63km/hr. |
| tornado | An intense windstorm that often forms within a severe thunderstorm. |
| There are _________ molecules of the atmosphere at greater heights. | fewer |
| continental polar air | air mass that forms over Alaska and Norther Canada. Air is Cold and dry |
| maritime polar air | Air that comes from the northern part of either the Pacific or Atlantic Ocean. The air is cool and moist. |
| maritime tropical air | Air that comes from the southern Pacific Ocean or the Gulf of Mexico. Air is warm and moist. |
| continental tropical air | The aire that comes from the deserts of Mexico and south west US. Air is hot and dry. |
| polar easterlies | wind blowing from the east brng air masses south and north toward the equator |
| prevailing westerlies | wind blowing from the west to east |
| northeast trade winds | winds that took sailors from Europe to the new world. |
| southeast trade winds | Winds blowing from southeast to northwest. |
| meteorologist | Scientist who studies the weather. |
| anemometer | measures wind speec |
| barometer | measures air pressure |
| dew point | the temperature at which water vapor in the air will condense. |