Abstract
An analytical study is made showing how second-order, non-geostrophic effects can modify a two-layer baroclinic wave system that grows exponentially from a small perturbation in a uniform zonal current. Many of the features observed on weather maps are seen to develop, including the relative meridional displacements and intensifications of the high and low pressure areas, the formation of a cutoff low aloft with a splitting of the jet stream, and the formation of zones of strong temperature gradient representing mid-tropospheric “fronts.” An analysis is also given to show the role of shear of the basic zonal current in the development of horizontal tilts of the amplifying waves.