What are some weather phenomena that cause low-level wind shear?

The presence of thunderstorms and microbursts is critical in understanding low-level wind shear because these phenomena create significant and often rapid changes in wind speed and direction within a short altitude range. Thunderstorms, particularly when they are strong or severe, can produce downdrafts, which, upon reaching the ground, can spread out in all directions and create shifting winds—a classic indicator of wind shear.

Microbursts, a specific type of downdraft associated with thunderstorms, can lead to extremely strong winds that descend rapidly and cause sudden, hazardous conditions for aircraft. These downdrafts can create severe turbulence and rapid changes in headwind or tailwind conditions as they interact with the surrounding atmosphere upon reaching the ground.

In contrast, clear skies without any weather phenomena do not generate low-level wind shear, as the absence of significant atmospheric disturbances allows for relatively stable wind conditions. Similarly, temperature inversions can cause changes in wind speed, but they are not as directly associated with the rapid and severe wind shifts that occur with thunderstorms and microbursts. Therefore, the combination of thunderstorms and microbursts provides a clear understanding of the mechanisms that contribute to low-level wind shear, making this choice the most accurate.