Numerical simulations of low-CAPE flows over a mountain ridge

In a recent study, the authors performed numerical simulations of conditionally unstable flows past a mesoscale mountain ridge in order to investigate the statistically stationary features of the solution precipitation characteristics for intermediate-to-high values of convective available potential energy (CAPE). That study proposed a functional dependence of the rain rate on three parameters, related respectively to the triggering and the orographic forcing of convection and to the ratio of the advective to convective time scales. The present study extends that analysis to cover larger regions of the parameter space, including experiments corresponding to a wider range of CAPE. It is found here that the low-CAPE, moderate-wind experiments do not fit the functional dependence for rain rate amount and location proposed in the authors’ previous study. The analysis of the present solutions suggests that two additional nondimensional parameters should be taken into account.