Solutions to a model of a front forced by deformation

A semi‐geostrophic deformation model of a front studied by B. J. Hoskins and F. P. Bretherton is studied further. It is shown that a unique solution of the Lagrangian conservation laws governing the motion can still be constructed after the front has formed. This solution shows that separate upper and lower fronts propagate into the fluid, and are separated by a region where only smooth variations occur. Finite difference solutions of the primitive equations are also given which converge to a front with the correct mean slope and maximum long‐front velocity but without the correct variation in slope through the depth of the fluid.