| A | B |
|---|
| air-mass thunderstorm | type of thunderstorm in which air rises because of unequal heating of Earth's surface within a single air mass and is most common during the afternoon and evening. |
| mountain thunderstorm | occurs when an air mass rises from orographic lifting, which involves air moving up the side of a mountain |
| sea-breeze thunderstorm | local air-mass thunderstorm that commonly occurs along a coastal area because land and water store and release thermal energy diffferently |
| frontal thunderstorm | type of thunderstorm usually produced by an advancing cold front, which can result in a line of thunderstorms hundreds of kilometers long, or, more rarely, an advancing warm front, which can result in a relatively mild thunderstorm |
| stepped leader | The channel of partially charged air; the breakdown in charges in between positive and negative regions |
| return stroke | a branch channel of positively charged ions that rushes upward from the ground to meet the stepped leader |
| supercell | extremely powerful, self-sustaining thunderstorm characterized by intense, rotating updrafts |
| downburst | violent downdrafts that are concentrated in a local area |
| tornado | violent, whirling column of air in contact with the ground that forms when wind direction and speed suddenly change with height, is often associated with a supercell, and can be extremely damaging |
| Fujita tornado intensity scale | classifies tornadoes according to the wind speed, duration, and path of destruction on a scale ranging from F0 to F5 |
| tropical cyclone | large, low-pressure, rotating tropical storm that gets its energy from the evaporation of warm ocean water and the release of heat |
| eye | calm center of a tropical cyclone that develops when the winds around its center reach at least 120 km/h |
| eyewall | band where the strongest winds in a hurricane are usually concentrated, surrounding the eye |
| Saffir-Simpson hurricane scale | classifies hurricanes according to wind speed, potential for property damage, and potential for flooding in terms of the effect on the height of sea level on a scale ranging from Catagory 1 to Catagory 5 |
| storm surge | occurs when powerful, hurricane-force winds drive a mound of ocean water toward the shore, where it washes over the land, often causing enormous damage |
| drought | extended period of well-below-average rainfall, usually caused by shifts in global wind petterns, allowing high-pressure systems to remain for weeks or months over continental areas |
| heat wave | extended period of above-average temperatures caused by large, high-pressure systems that warm by compression and block cooler air masses |
| cold wave | extended period of below-average temperatures caused by large, high-pressure systems of continental polar or arctic origin |
| windchill index | measures the windchill factor, by estimating the heat loss from human skin caused by a combination of wind and cold air |
