What are the characteristics of stable air?
AGood visibility, showery precipitation, and cumuliform clouds.
BPoor visibility, steady precipitation, and stratiform clouds.✓
CTurbulence, cumulonimbus development, and gusty surface winds.
Why →Stable air resists vertical movement. Characteristics: stratiform (flat, layered) clouds, steady (non-showery) precipitation, poor visibility due to trapped pollutants and haze, and smooth (non-turbulent) air. The temperature inversion is a classic stable air scenario.
The trap →Showery precipitation and cumuliform clouds indicate unstable air. Cumulonimbus and gusty winds are severe unstable air. Stable air is the smooth, hazy, steady-rain scenario.
Field note →Stable air can be deceptive for drone pilots. The smooth flight conditions are excellent, but the trapped haze and low visibility can eliminate visual line of sight. Always check visibility, not just turbulence.
SOURCE → PHAK Chapter 12, FAA UAG Sample Question 36CHECKED JUL 16ACS III.A.K1MED