When is turbulence in the lower troposphere most likely to occur?

• A. When the 1000-500 mb thickness contours are far apart
• B. When the 1000-500 mb thickness contours are close together
• C. During stable atmospheric conditions
• D. In a high-pressure system

Answer: (B)

Turbulence in the lower troposphere is most likely to occur when the 1000-500 mb thickness contours are close together. This situation typically indicates a strong vertical wind shear and rapid changes in atmospheric pressure over a relatively short distance, which can lead to unstable air currents. These conditions create varying wind speeds and directions, which are prime contributors to turbulence.

When the contours are close together, it suggests that there is a steep gradient in temperature and pressure, often associated with active weather patterns that can enhance turbulence. For instance, if cold air is situated above warmer air, the contrast can generate significant turbulence, especially during periods of frontal passage or strong weather systems.

On the other hand, when the thickness contours are far apart, it usually indicates a stable atmosphere with uniform conditions, resulting in less turbulence. Stable atmospheric conditions, which are typically associated with widespread high-pressure systems, do not favor turbulence because they promote laminar flow rather than chaotic air movements.