Cyclonic shear

From Glossary of Meteorology

cyclonic shear

Horizontal wind shear of such a nature that it contributes to the cyclonic vorticity of the flow, that is, it tends to produce cyclonic rotation of the individual air particles along the line of flow.

In the Northern Hemisphere, cyclonic shear is present if, when one faces downwind, the wind speed increases from left to right across the direction of flow; the opposite is true in the Southern Hemisphere.
Compare anticyclonic shear.