The Fleet Numerical Weather Central Tropical Cyclone Model: Comparison of Cyclic and One-Way Interactive Boundary Conditions

One of the major problems in the development of limited-area models is the specification of reasonable boundary conditions. The results of the use of one-way interactive boundary conditions in the Fleet Numerical Weather Central (FLENUMWEACEN) coarse-mesh tropical cyclone model are discussed. Given analyzed fields in 12-hr intervals, boundary values are linearly interpolated in time for each time step. Smoothing is done near the boundaries to minimize the excitation of gravity waves. This procedure is conducted through 72 hr. The results are compared to forecasts made by the current FLENUMWEACEN coarse mesh model that uses insulated, free-slip walls on the N-S boundaries and cyclic conditions in the E-W direction.