Earth’s Atmosphere: Lesson 7 Thunderstorms

Ch 11/12/13 Earth’s Atmosphere Study Guide Name: ______________________________ Date: ___________ Period: ____ Lesson 7 Thunderstorms… 1. Where do the majority of thunderstorms occur in the USA? The majority of thunderstorms occur in the central and southeastern regions of the United States, often referred to as "Tornado Alley" and the "Dixie Alley. 2. How, when, and where do the following types of thunderstorms form? Which types affect us here in the Piedmont? a. Air mass (mountain/orographic) Form when moist air is forced to rise over mountains, leading to orographic lifting and the development of thunderstorms on the windward side of the mountains. They can affect the Piedmont indirectly by influencing weather patterns b. Air mass (sea-breeze) Form when a sea breeze front collides with a preexisting boundary or convergent zone, leading to the development of thunderstorms along the boundary. These can directly impact the Piedmont region c. Frontal (cold) Form along the leading edge of a cold front, where warm, moist air is lifted rapidly by the advancing cold air. They can affect the Piedmont region as cold fronts pass through d. Frontal (warm) Form when warm, moist air is lifted over a retreating warm front, leading to the development of thunderstorms. These can impact the Piedmont as warm fronts pass through 3. List the 3 stages in the development of a thunderstorm in order. What occurs in each stage? a. Cumulus Stage: Moist, warm air rises, cools, and condenses to form cumulus clouds. Updrafts dominate this stage b. Mature Stage: Downdrafts and updrafts coexist within the thunderstorm. Heavy rain, lightning, thunder, and sometimes hail occur during this stage c. Dissipating Stage: Downdrafts dominate, and the storm weakens as the supply of warm, moist air is depleted. Rainfall diminishes, and the storm dissipates 4. Know the following terms – a. Thunderstorm A storm characterized by thunder and lightning, often accompanied by heavy rain, strong winds, and sometimes hail or tornadoes b. Anvil The flat, spreading top of a mature thunderstorm, often shaped like an anvil c. Supercell A severe thunderstorm characterized by a persistent rotating updraft called a mesocyclone, which can produce intense rainfall, large hail, strong winds, and tornadoes 5. What is lightning and how does it form? Use the terms stepped leader, return stroke, channel, and lightning in your answer. Lightning forms when a stepped leader, a channel of ionized air, extends downward from a cloud towards the ground. When the stepped leader nears the ground, a return stroke travels upward along the ionized channel, creating a bright flash of light and the sound of thunder 6. Where is the safest place to be during a thunderstorm? The safest place during a thunderstorm is indoors, away from windows, and preferably in a sturdy, enclosed building or vehicle 7. Why do we hear lightning? What is the sound of lightning called? We hear lightning because of the rapid expansion and heating of air caused by the electrical discharge, creating a shockwave known as thunder 8. What is a downburst? How does it differ from a tornado? A downburst is a strong downdraft that causes damaging winds at the surface. It differs from a tornado in that a tornado is a rotating column of air extending from a thunderstorm to the ground 9. What are the 2 types of downbursts? Which type of downburst is the most deadly? The two types of downbursts are microbursts and macrobursts. Microbursts are smaller in scale and shorter in duration but can still be deadly due to their intense winds. Macrobursts are larger and longer-lasting but occur less frequently 10. Why do floods occur? Floods occur when there is an overflow of water onto land that is normally dry. This can happen due to heavy rainfall, snowmelt, ice jams, or the failure of dams or levees