Private Pilot Private Exam

Which conditions should be expected beneath a low-level temperature inversion layer when relative humidity is high?

1. Clear air and good visibility

2. Smooth air, poor visibility, fog, haze, or low clouds

3. Strong winds and turbulent conditions

4. Warm air and clear skies

The correct answer is: Smooth air, poor visibility, fog, haze, or low clouds

When relative humidity is high beneath a low-level temperature inversion layer, the expected conditions typically include smooth air, poor visibility, fog, haze, or low clouds. A low-level temperature inversion occurs when a layer of warmer air traps cooler air at the surface, which can lead to stable atmospheric conditions. High humidity in this situation can cause the air to reach its dew point, resulting in condensation and the formation of fog or low clouds. The stable air does not support vertical mixing, thereby leading to a lack of turbulence but the presence of moisture reduces visibility significantly due to fog and haze. In contrast, clear air and good visibility would be less likely in such conditions, especially with high humidity and an inversion layer present. Strong winds and turbulent conditions are typically indicative of unstable atmospheric conditions, which contradict the stability promoted by temperature inversions. Warm air and clear skies would also not align with the high humidity and the effects of an inversion layer, as the presence of humidity usually leads to some form of cloud or fog formation.