Pattern-based signal/noise separation is a common technique to suppress multiples. It can be formulated in the t-x domain using non-stationary Prediction Error Filters (PEF). One can obtain a kinematically correct model of the multiples by downward continuation. The CMP gather and the corresponding multiple estimate are characterized by a space varying PEF. After applying a simple separation technique one can obtain CMP gathers where the multiple energy is significantly attenuated. The method is applied to synthetic and 2-D field CMP gathers.