What weather condition is typically associated with unstable air?

Unstable air is characterized by its tendency to rise, which can lead to the development of convective weather phenomena such as thunderstorms. When air is unstable, it means that warmer, lighter air is able to rise rapidly through cooler, denser air. This rising air can lead to the formation of cumulonimbus clouds, which are often associated with thunderstorms.

Good visibility in unstable conditions is typically the case when there are no obstructive particles such as heavy rain or snow. This allows for clearer skies, especially when compared to stable air situations, which might trap moisture and lead to persistent cloud cover or fog. Consequently, the presence of unstable air generally correlates with good visibility conditions, barring specific environmental impacts like blowing sand or snow.

Other options highlight specific weather conditions that do not directly represent the effects of unstable air. For example, heavy thunderstorms and fog indicate instability but also include limited visibility, while persistent cloud cover and mist suggest a stable environment where air remains close to the surface. Thus, good visibility is an accurate description of the conditions one might expect in the presence of unstable air.