| A | B |
|---|
| air mass | A huge body of air that has similar temperature, pressure, and humidity throughout. |
| tropical (air mass) | A warm air mass that forms in the tropics and has low air pressure. |
| polar (air mass) | A cold air mass that forms north of 50° north latitude or south of 50° south latitude and has high air pressure. |
| maritime (air mass | A humid air mass that forms over oceans. |
| continental (air mass) | A dry air mass that forms over land. |
| front | The area where air masses meet and do not mix. |
| occluded | Cut off, as the warm air mass at an occluded front is cut off from the ground by cooler air beneath it. |
| cyclone | A swirling center of low air pressure. |
| anticyclone | A high-pressure center of dry air. |
| storm | A violent disturbance in the atmosphere. |
| lightning | A sudden spark, or energy discharge, caused when electrical charges jump between parts of a cloud or between a cloud and the ground. |
| tornado | A rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to touch Earth’s surface, usually leaving a destructive path. |
| hurricane | A tropical storm that has winds of 119 kilometers per hour or higher; typically about 600 kilometers across. |
| storm surge | A dome of water that sweeps across the coast where a hurricane lands. |
| evacuate | To move away temporarily. |
| flash flood | A sudden, violent flood that occurs within a few hours, or even minutes, of a heavy rainstorm. |
| meteorologists | Scientists who study the causes of weather and try to predict it. |
| El Niño | An abnormal climate event that occurs every 2 to 7 years in the Pacific Ocean, causing changes in winds, currents, and weather patterns that can lead to dramatic climate changes. |
| isobars | Lines on a map joining places that have the same air pressure. |
| isotherms | Lines on a map joining places that have the same temperature. |
