FAA Ground School Practice Test

If the temperature/dewpoint spread is small and decreasing with a temperature of 62 degrees F, what weather is likely to develop?

1. Clear skies

2. Thunderstorms

3. Fog or low clouds

4. High winds

The correct answer is: Fog or low clouds

When the temperature and dewpoint spread is small and continues to decrease, it indicates that the air is becoming more saturated. In this scenario, with a temperature of 62 degrees Fahrenheit and a small temperature/dewpoint spread, the atmosphere is likely transitioning towards a state where condensation can occur. Fog or low clouds form when the air temperature drops to the dewpoint, resulting in visible moisture in the air. This often happens under stable conditions when the air cools, allowing it to reach saturation. As the spread narrows, it suggests that the air is approaching its moisture capacity, which is conducive to the formation of these phenomena. The alternative options don't fit as well with the conditions described. Clear skies typically occur when there is a significant difference between temperature and dewpoint, indicating dry air. Thunderstorms generally develop from rising, unstable air rather than a stable, saturated atmosphere. High winds are usually associated with pressure differences and fronts rather than a small temperature/dewpoint spread. Thus, the likelihood of fog or low clouds developing is strongly supported by these atmospheric conditions.