Rolling Element Bearings (REB) are one of the key components of rotating machinery. Their correct functioning and failure have been the object of many studies and today many models are available that can reproduce their vibration response. Most of them are applied for diagnosis purposes and simulate the bearing behaviour in steady state considering fixed surface defect. Such vibration signals are useful to perform bearing diagnosis but they lack the necessary information for predictive algorithms conceived for prognosis applications. The objective of the work presented here is using an already existing dynamic model to simulate vibration signals under unsteady degradation conditions. Different degradation profiles have been proposed to simulate the evolution of local surface defects on the bearing components to form a synthetic database for future prognosis applications. The obtained signals can be very useful for data-drive prognosis algorithm training. As proof, they were used for RUL (Remaining Useful Life) estimation with a simple approach and proved to be effective.