FAA Instrument Rating Airplane (IRA)Weather and Weather ServicesEasy
Which three conditions are necessary for the development of a thunderstorm?
- ASufficient water vapor, an unstable lapse rate, and a lifting mechanism
- BStrong upper-level winds, dry air, and a stationary front
- CHigh pressure, stable air, and moisture
- DLow humidity, temperature inversion, and calm winds
Show answer & explanationAnswer & explanation
Correct answer: A. Sufficient water vapor, an unstable lapse rate, and a lifting mechanism
Thunderstorms require three basic ingredients: adequate moisture (water vapor) to form clouds and precipitation, an unstable atmosphere (steep lapse rate) to sustain vertical development, and a lifting mechanism such as a front, convergence, or heating to initiate the updraft.
Why the other options are wrong
- B. Dry air inhibits cloud and precipitation formation, working against thunderstorm development.
- C. High pressure and stable air suppress vertical development and inhibit thunderstorm formation.
- D. Low humidity and a temperature inversion both suppress the instability needed for thunderstorms.
Thunderstorm Ingredients
Three conditions required for thunderstorm formation: moisture, instability, and a lifting mechanism.
- Moisture provides fuel for cloud/precipitation growth
- Instability (steep lapse rate) allows strong vertical currents
- Lifting mechanisms include fronts, convergence, or surface heating
Memory trick: MIL: Moisture, Instability, Lift — the recipe for storms.