Potential kinematic and thermodynamic properties of RFDs are investigated using a 1.5 dimension downdraft model that is driven by hydrometeor fields. This downdraft model uses conservation equations for vertical momentum, temperature, mixing ratios of water vapor and cloud water, number concentration densities of raindrops and graupel/hail, and ice-water fraction of graupel/hail. Microphysical processes include saturation adjustment, evaporation/condensation of raindrops, evaporation/condensation of melting graupel/hailstones, melting of graupel/hailstones, and shedding of melting graupel/hailstones. Environmental conditions are set using prescribed soundings that span a wide range of conditions to illustrate the range of simulated-RFD outcomes. The initial model state is hydrostatically balanced to ensure that subsequent evolution results only from hydrometeors, which are inserted with the same properties at the same altitude at each time step.
Results indicate that downdraft strength is strongly dependent on environmental lapse rates of temperature. Moreover, the vertical distribution of these lapse rates is a strong determinant of the maximum originating altitude of air parcels that descend to the surface. In addition to being sensitive to environmental conditions, modeled downdrafts are also sensitive to the properties of the hydrometeor fields that drive them. From these effects and the expected vertical temperature profiles of RFD environments, potential explanations of VORTEX observations will be provided.