Modal and nonmodal baroclinic waves

Solution of the initial-value problem for the Eady model is presented. In the presence of boundaries, normal mode waves as well as non-modal waves exist. Energy extracted fro the mean flow during the initial development of a perturbation is found excite the the persistent normal modes. It is suggested that this process may be important to cyclogensis and in providing energy to neutral or near-neutral normal modes. In particular, the Petterssen criterion for cyclogenesis is clarified.