A two-dimensional, linear, Boussinesq, inviscid, hydrostatic model is used to simulate the flow over an elevated diabatic source and a surface diabatic source. The elevated source is identified as being due to cooling by melting, layer, capped by a much less stable layer aloft. This creates a strong change in the vertical wave number, which might lead to resonant amplification of mesoscale perturbations, just as in mountain wave theory. Comparison with sounding data suggests that this amplification mechanism is potentially important for precipitation enhancement due to melting. ¿ American Geophysical Union 1989