Horizon scale environments in black holes are composed of accretion flows, where radiation at observable wavelengths is mostly synchrotron emission driven by MHD turbulence. General relativistic ray tracing is employed on GRMHD simulations to study the observational manifestations of phenomena in black hole accretion disks. I will present methods of inferring variability in VLBI observables obtained from ray traced GRMHD realizations.
