Cloud motion that appears to differ relative to other nearby cloud elements, e.g. clouds moving from left to right relative to other clouds in the foreground or background. Cloud rotation is one example of differential motion, but not all differential motion indicates rotation. For example, horizontal wind shear along a gust front may result in differential cloud motion without the presence of rotation.
DIFFERENTIAL MOTION
Meaning of DIFFERENTIAL MOTION in English
A comprehensive English glossary of weather. Полный английский глоссарий погоды. 2012