Previous studies have shown that the flare activity of solar active regions is intrinsically linked with the vorticity of solar subsurface flows on temporal and spatial scales comparable to the size and lifetime of active regions. We derive the vorticity vector and the kinetic helicity density of subsurface flows applying ring-diagram analysis to Global Oscillation Network Group (GONG) data. We are beginning to address the question whether the measured vorticity of subsurface flows associated with active regions can help to improve flare forecasting. For this purpose, we apply statistical tests based on discriminant analysis to several subsurface flow parameters with the goal to differentiate between flaring and non-flaring active regions. We are especially interested in the temporal evolution of vorticity and kinetic helicity and study their relation to magnetic flux and flare activity of active regions. We will present the latest results.