A multistage error-growth conceptual model for mesoscale predictability

A multistage error-growth conceptual model was developed by examining the forecast difference between two cloud-resolving simulations. In the initial stage, errors first grow from small-scale convective instability but then quickly saturate at the convective scales on time scales of 0(1 h). In the transitional stage, the errors transform from convective-scale unbalanced motions through geostrophic adjustment and/or cold-pool dynamics. In the final stage, the balanced components of the errors project onto the large-scale flow and grow with the background baroclinic instability. An examination of the difference-error energy budget revealed that bouyancy production due mostly to moist convection is comparable to shear production due to nonlinear advection.