Using the gridded atmospheric
motion vector output u and v AMV components at the specified
level, vorticity is computed using finite differencing of
(dv/dx - du/dy), where u and v are the wind components
and x and y are the horizontal grid spacing.
Vorticity is a measure of curvature in atmospheric flow. A
positive value indicates counter clockwise motion in the northern
hemisphere and clockwise motion in the southern hemisphere.
A positive vorticity environment is conducive to storm development.
For more AMV information, please visit the
International Winds Working Group (IWWG)