| Question | Answer |
|---|---|
| Thunderstorms | Localized storms involving lightning, thunder, strong winds, heavy rains, and sometimes hail or tornadoes |
| Stable | The air is this when currents of rising air are stopped by adiabatic cooling and thus do not rise to great altitudes |
| Unstable | The air is this when warm air is near the ground but there is very cool air at higher altitudes |
| Cumulus stage | The stage of a thunderstorm in which ice crystals and super-cooled water droplets begin to develop |
| Mature stage | During which the thunderstorm reaches the peak of its strength (the beginning is marked by the arrival of precipitation) |
| Downdrafts | Concentrated blasts of cool wind that originate from strong, localized downdrafts |
| Microbursts | The smallest, most intense downbursts |
| Dissipating stage | In which the clouds begin to evaporate because it's power supply is cut off |
| Cell | Updraft system |
| Single-cell thunderstorm | A thunderstorm containing one cell |
| Multiple-cell thunderstorm | Thunderstorms with more than one cell |
| Squall line | A multiple-cell thunderstorm that is a long line of advancing thunderstorms usually moving ahead of a cold front |
| Supercell | The most powerful type of thunderstorm; it is single-celled |
| Lightning | An abrupt discharge of electricity through the air that produces a quick flash of bright light |
| Stepped leader | An electron stream |
| The positive charge on the ground, attracted by the approaching stepped leader, launches upward in a(n) ___ ___ that rises to meet the stepped leader. | positive streamer |
| Return stroke | The upward flow of positive charge that forms the flash of light that can be seen |
| Dart leader | A second leader that travels down the channel of the first strike |
| Thunder | A shock wave of sound |
| ___ ___-___-___ lightning is lightning in which the stepped leader travels from a negative region of the cloud down to the ground. | Negative cloud-to-ground lightning |
| ___ ___-___-____ occurs when a stepped leader begins from the cloud's positively charged upper region. | Positive cloud-to-ground lightning |
| ___ ___ is lightning that usually causes objects it strikes to catch on fire. | Hot lightning |
| Lightning can also strike ___-___-___, although this type of lightning does not occur frequently. | ground-to-cloud |
| 30-30 rule | A principle says if there are 30 seconds or less between seeing lightning strike and hearing thunder, stay in a safe place until there has been no thunder for at least 30 minutes |
| ___-___-___ lightning occurs between two clouds or between positive and negative sections of the same cloud. | Cloud-to-cloud |
| ___ ___ is a rare phenomenon that consists of a small sphere of electricity that seems to float in the air for several seconds. | Ball lightning |
| Tornado | A narrow funnel of powerful, rapidly whirling wind that stretches from a cloud to the goround |
| Common names for tornadoes are ___ or ___, although to a meteorologist a ___ refers to any low-pressure system in which winds rotate in a direction caused by the Coriolis effect. | twisters, cyclones, cyclone |
| The most powerful tornadoes are believed to form from the ___ ___ found in many super-cell thunderstorms. | rotating updrafts |
| Mesocyclone | A rotating updraft |
| When an inner region of rotating air reaches the ground, it becomes a what? | tornado |
| Wall cloud | A large, rotating cylindrical extension form the base of the supercell |
| Condensation funnel | The most distinctive visual feature of a tornado |
| Tornado Alley | The Mississippi Valley and eastern Great Plains of the United States |
| The ___ ___ classifies tornadoes based on intensity and area. | Fujita scale |
| Enhanced Fujita Scale | The scale currently used to rank tornado intensity |
| Waterspout | A tornado that forms over water |
| Dust devil | A dust devil is like a tornado but a dust devil starts on the ground and is not associated with a cloud |
| Tornado warning | Means a tornado has been reported or favorable winds for a tornado have been spotted on a weather radar |
