Prediction of Nine Explosive Cyclones over the Western Atlantic Ocean with a Regional Model

A series of 14 numerical experiments were conducted using the Pennsylvania State University/National Center for Atmospheric Research mesoscale model on nine cases of explosive marine cyclogenesis. The main objective was to identify key factors that are important to short-range prediction of explosive cyclones. We found that the intensity and structure of the simulated cyclones were sensitive to the details of precipitation parameterization. The grid-resolvable-scale precipitation associated with the mesoscale slantwise ascent in the vicinity of the warm front was crucial for rapid development. The upright convective precipitation played a relatively unimportant role. Surface energy fluxes had little effect on the development during the 24-h period of rapid cyclogenesis. The pattern of upward and downward fluxes while the storms were in progress was not favorable for storm intensification. Small case-to-case variation was found among the nine-case ensemble in the resulting deepening due to changes...