Gradient Wind non-geostrophic winds which blow parallel to isobars
Geostrophic winds exist in locations where there are no frictional forces and the isobars are striaght. However, such locations are quite rare. Isobars are almost always curved and are very rarely evenly spaced.
A steady, horizontal wind flowing along curved isobars is called gradient wind. Where there is imbalance between the pressure gradient and Coriolis forces.
When the pressure gradient force is greater than the Coriolis force, the flow takes on a curved path around low pressure.
the same as geostrophic wind, but blowing parallel to curved isobars or contours; the curved airflow pattern around a pressure center results from a balance among pressure-gradient force, coriolis force, and centrifugal force.
A theoretical wind that results from a balance between the pressure gradient, Coriolis and centrifugal forces. It is a better approximation than the geostrophic wind as it accounts for the curvature of real weather systems.
Gradient wind - Wind that flows parallel to the isobars, but non-linearly.
~ A theoretical horizontal wind that blows parallel to curved isobars or contours above the friction layer.
Granules A network of huge, irregularly shaped convective cells in the sun's photosphere.
A steady horizontal air motion along curved parallel isobars or contours in an unchanging pressure or contour field, assuming there is no friction and no divergence or convergence.
In explaining the geostrophic wind, we assumed that the isobars were straight lines. This is seldom the case in practice, so we must allow for curvature of the isobars, which introduces centrifugal forces, and thus a cyclostrophic component to the winds.
Pressure gradient wind
The wind that results from the pressure gradient. The greater the pressure gradient between two points, the greater the wind. The pressure gradient wind blows parallel to the isobars with (on the northern hemisphere) lower pressure on the left.
Also called ~ level. Geostrophic-wind scale A graphical device used for the determination of the speed of the geostrophic wind from the isobar or contour-line spacing on a synoptic chart.
= speed of the wind at height = ~ at gradient height = exponential coefficient
 Wind turbines ...
At the surface the wind is in the opposite direction to the ~. Rotors are often associated with extreme and turbulence an are often marked by a rotor cloud such as the helm bar. Rotor clouds belong to the altocumulus lenticularis family.
A good 'first read' when trying to get to grips with the finer points of, for example, the ~ equation. Even tells you how to construct your own tephigram! Don't be put off by the mathematics early on in the book though - there is plenty of good general meteorology that will interest all.
Surface winds are measured by anemometer and wind vane; winds aloft by such systems as pilot balloon, radiosonde, or aircraft navigational techniques. See also circulation, general circulation, turbulence, geostrophic wind, ~, local winds, Beaufort wind scale, draft, cyclone, whirlwind, ...
See also: What is the meaning of Gradient, Wind, Force, Pressure, Geostrophic Wind?