When air is stable, which weather phenomena is least likely to occur?

When air is stable, it tends to resist vertical motion, which means that upward airflow is limited. This stability inhibits the development of strong convection currents that are typically necessary for severe thunderstorms to form. Severe thunderstorms require significant lifting of warm, moist air, which leads to the intense vertical development seen in these storms. In stable conditions, the likelihood of this lifting occurring is greatly reduced, making severe thunderstorms the least likely of the listed phenomena to develop.

Conversely, strong gusty winds can still occur in stable air under certain atmospheric conditions, often due to pressure differences or frontal passages. Continuous rain may be associated with stable air that allows for persistent moisture to remain in a region. Similarly, fog formation is common in stable conditions, especially when the air cools to its dew point. Thus, stable air significantly limits the potential for severe thunderstorms, making it clear why this is the correct answer.