The paradox that flow obeying this condition simultaneously increases the horizontal temperature gradient and decreases the vertical shear can be resolved by introducing a forcing function into the omega equation. Jule Charney is credited with developing a theory based on flows nearly obeying this condition in order to analyze atmospheric disturbances. (15[1])The namesake adjustment to this condition from a perturbed state is demonstrated by taking potential vorticity to be conserved, and then solving the shallow water equations for a fluid with a height discontinuity. This condition holds for nearly all (*) synoptic-scale flows at middle latitudes. This condition holds for flows with a Rossby number much less than one. Winds that satisfy this condition always blow parallel to isobars. For 10 points, name this condition in which the Coriolis force is exactly balanced by the pressure gradient force. ■END■