Wind shear is a difference in either wind speed or direction over a fairly short distance in the atmosphere. Wind shear can be divided into two different types: horizontal and vertical wind shear.
schematic of the downward motion of the air until it hits ground.
Weather situations when the Wind shear is observed happen:
- At weather fronts when the temperature difference across the front is 5 °C or more, and the front moves at 15 kt or faster.
- At low level jets when a significant low level vertical wind shear can develop near the lower portion of the low level jet.
- At mountains when winds blow over and create vertical shear on the lee side.
- At inversions when on a clear and calm night a radiation inversion is formed near the ground.
- At downbursts when an outflow boundary moves away from a thunderstorm.
- At sailing when wind shear affects sailboats by presenting a different wind speed and direction at different heights along the sailing mast.