What weather phenomena can be expected from moist, unstable air and very warm surface temperatures?

The presence of moist, unstable air combined with very warm surface temperatures creates an environment conducive to significant convective activity. In such conditions, the warm air near the surface heats up and starts to rise. As this air ascends, it cools and moisture in the air condenses to form clouds. When the rising air is unstable, it can lead to the development of strong updrafts that facilitate the growth of cumulonimbus clouds, which are associated with thunderstorms.

Cumulonimbus clouds are towering and can produce severe weather phenomena, including thunderstorms, heavy rainfall, and even severe turbulence. The instability signifies that the air is buoyant enough to cause rapid vertical movement, which is essential for the development of these types of clouds.

The other options reflect weather phenomena that are not typically associated with moist, unstable air and high surface temperatures. For instance, fog and low stratus clouds typically arise in stable air conditions rather than instability. Continuous heavy precipitation could occur, but it is more specifically linked to the maturity of a system and not simply the presence of warm, moist air alone. Finally, clear, calm conditions generally occur under stable atmospheric conditions, which contrasts sharply with the instability indicated by the question.