Model that includes a well resolved stratosphere. It is based on a stochastic approach, where an ensemble of monochromatic waves is built up, by launching few waves at each time step, and by cumulating the effect of these waves via an AR1 relation between the GWs tendency at a given time step and that at the next time step. Some properties of each waves are chosen randomly, like their wavenumbers and frequencies and with fixed probability distribution. Their amplitude nevertheless, is directly related to the precipitation, translating it in an heating rate and using linear theory to predict the amplitude of the waves such a heating can produce.