A forecast for a remote pilot's work site shows plenty of moisture (high dewpoints) and a conditionally unstable air mass this afternoon. According to the Aviation Weather Handbook, what else is needed for thunderstorm cells to form?
- AA surface-based temperature inversion that traps the moist air
- BBelow-freezing temperatures at the surface
- CA lifting mechanism, such as a front, upslope flow, or a sea breeze
Show answer and explanation
Correct answer: C. A lifting mechanism, such as a front, upslope flow, or a sea breeze
Thunderstorm cells need three ingredients: sufficient water vapor, unstable air, and a lifting mechanism. With moisture and a conditionally unstable air mass already present, a lifting mechanism strong enough to release the instability is the missing piece. Examples include fronts, upslope flow, outflow boundaries, and sea breezes.
- A. Incorrect. Wrong. The three ingredients for thunderstorm cell formation are sufficient water vapor, unstable air, and a lifting mechanism; an inversion is not one of them.
- B. Incorrect. Wrong. Freezing surface temperatures are not among the three ingredients: sufficient water vapor, unstable air, and a lifting mechanism.
- C. Correct. A conditionally unstable air mass needs a lifting mechanism strong enough to release the instability. Fronts, upslope flow, and sea breezes are examples.
FAA-H-8083-28B Aviation Weather Handbook, 22.2 Necessary Ingredients for Thunderstorm Cell Formation Thunderstorm cell formation needs three ingredients: sufficient water vapor, unstable air, and a lifting mechanism
FAA-H-8083-28B Aviation Weather Handbook, 22.2 Necessary Ingredients for Thunderstorm Cell Formation A conditionally unstable air mass needs a lifting mechanism strong enough to release the instability. Lifting mechanisms include converging winds around surface lows and troughs, fronts, upslope flow, drylines, outflow boundaries generated by prior storms, and local winds, such as sea breeze, lake breeze, land breeze, and valley breeze circulations.