Explain thunderstorms, tornadoes, and hurricanes as different-scale results of warm, moist, rising air, and describe the conditions each needs to form.
Every storm on this list starts the same way: warm, moist air rising quickly. As that air rises, it cools, its water vapor condenses into towering clouds, and it releases energy that fuels even faster rising, called an updraft. A basic thunderstorm needs warm, humid air near the ground and a way to get it rising, like daytime heating or a front pushing under it; the result is a tall cloud, heavy rain, lightning, and thunder.
A tornado forms when a severe thunderstorm's updraft combines with winds blowing at different speeds and directions at different heights, called wind shear, which can tip a horizontal spinning tube of air upright into a violent, narrow, spinning column that reaches the ground. A hurricane is a much larger system: it forms over warm ocean water, which evaporates huge amounts of moisture into a spinning mass of thunderstorms that can grow hundreds of miles wide, with the ocean's heat as its fuel supply. All three storms are, at heart, the atmosphere moving huge amounts of heat energy from one place to another.
Mastery looks like: They can explain warm, rising, moist air as the shared engine behind thunderstorms, tornadoes, and hurricanes, and name the one extra ingredient each needs to escalate.
Common stumbles: Treating the three storms as unrelated instead of the same basic process at different scales; forgetting a storm needs a continuing energy supply, heat and moisture, to keep going.