Note on Weather Computing and the so-called 2½-dimensional Model

The problem of setting up a system of equations by means of which the future large-scale flow pattern might be computed, using an electronic calculating machine, in a reasonable time and with maximum accuracy and efficiency, is discussed. Equations determining the development of a two-parameter, two-dimensional ‘model’, capable of representing the major features of motion of a baroclinic atmosphere, are derived. Tests of the model are made on some representative problems, the accurate three-dimensional solutions of which are known.