By constraining the perturbed velocity and temperature fields to vanish exponentially radially, the coupled system of equations can be seen to give a unique form of the temperature lapse rate of the atmosphere which corresponds to the unstable regime. We then show that finite disturbances in the condensation rate, or equivalently smooth horizontal variation of the large scale fields, do not allow such localization of steady-state perturbations, though in the time-dependent case the possibility remains.