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| weather | the condition of the atmosphere as it is affected by temperature, atmospheric pressure, wind and water |
| air mass | a large body of air with consistent temperature and moisture content throughout |
| wind | the horizontal movement of air that occurs as a result of pressure differences between two air masses |
| thermal | a small, upward flow of warm air |
| convection cells | large wind patterns in Earth's atmosphere caused by convection |
| Coriolis effect | the bending of currents of air or water due to Earth's rotation |
| meteorologist | an individual who uses scientific principles to forecast the weather |
| dew point | the temperature at which more water condenses than evaporates in an air mass at a constant atmospheric pressure |
| cloud | a group of water droplets or ice crystals that you can see in the atmosphere |
| front | the border between two different air masses |
| cold front | a front that occurs when a cold air mass moves in and replaces a watm air mass |
| warm front | a front that occurs when a warm air mass moves in and replaces a cold air mass |
| jet streams | high-altitude, fst-moving winds |
| low-pressure center | a low pressure area created by rising warm air |
| high-pressure center | a high-pressure area created by sinking cold air |
| isobar | a line on a weather map that connects places that have the same atmospheric pressure |
| storm cell | a convection cell within a cloud that is associated with a storm |
| lightning | a bright spark of light that occurs inside a storm cloud, between a cloud and Earth's surface, or between two clouds |
| thunder | a sound that occurs when a lightning spark heats air and the air expands |
| cyclone | a low-pressure center surrounded by rotating winds |
| hurricane | a tropical cyclone with wind speeds of at least 74 miles per hour (119 kilometers per hour) |
| tornado | a system of rotating winds around a low-pressure center; a tornado is smaller than a hurricane, but has faster winds |
| climate | the long-term record of weather patterns and includes the temperature, precipiration, and wind for a region |
