On derivation and interpretation of Kuo-Eliassen equation

The Kuo–Eliassen equation provides a balance condition for both tropical–cyclone like vortex systems as well as zonally–symmetric meridional circulations. This condition is examined with the former application more in mind. The condition is derived more ped- agogically based on the bounded derivative method. Some physical interpretations as well as basic mathematical remarks on this condition are provided. Analogy with quasi–geostrophic system is also remarked.