36 What are characteristics of a moist, unstable air mass?
A. Turbulence and showery precipitation.
This is correct.
From: FAA-H-8083-25B, "Pilot’s Handbook of Aeronautical Knowledge"
Chapter 12, "Weather Theory"
Page 12-17, Air Masses
"This creates an unstable air mass with good surface visibility. Moist, unstable air causes cumulus clouds, showers, and turbulence to form."
The operative word is "unstable".
This illustration in Chapter 6, Stable and Unstable Air, shows the main difference of stable and unstable air. The illustration shows a mountain deflecting an air mass, but it could as easily be another air mass, as when a cold front collides with a warm front, or when an offshore wind meets the land.