LBAR (Limited area sine transform BARotropic) is a two-dimensional track prediction model which solves the shallow-water equations initialized with vertically averaged (850-200 hPa) winds and heights from the Aviation Run of the MRF global model (Horsfall et al 1997). An idealized symmetric vortex and a constant vector (equal to the initial storm motion vector) are added to the global model analysis to represent the storm circulation. The boundary conditions are obtained from the global model forecast, and the model equations are solved using the spectral sine transform technique described by Chen et al (1997). To make LBAR timely, initial and boundary conditions are obtained from the 6 hr old MRF forecast. LBAR was developed as an operational version of the experimental VICBAR model (Aberson and DeMaria 1994).

Here is the science JG - I would say it is as clear as mud.