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Weather theoryQuestion 342 of 934

An air mass moves over a warmer surface. What does this create?

  1. A stable air mass with poor surface visibility
  2. An unstable air mass with good visibility
  3. A stable layer of smooth air near the ground
  4. A layer of low stratus and fog near the ground
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Correct answer: An unstable air mass with good visibility

Warming from below creates convective currents. Cumulus clouds, showers, and turbulence can form.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 12: Weather Theory — Air Masses and Fronts, page 302

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Questions last reviewed: 18 October 2026