Gradient Wind 

  1. Wind flowing parallel to pressure isobars or contours with low pressure on the left of the observer in the Northern Hemisphere; velocity such that the pressure gradient, Coriolis, and centrifugal force acting in the area are in balance.
  2. Wind created by differing barometric pressures between high- and low-pressure systems. Velocity is generally five to 30 miles per hour, and wind shifts are usually gradual as systems move and shift.