A probabilistic fatigue damage analysis procedure which is coupled to a structural health monitoring system is discussed. The conceptual monitoring system includes a pair of ultrasonic sensors - a narrowband SAW generator and a harmonically matched SAW receiver. The sensors provide information of the current level of damage by monitoring the second harmonic in the SAW signal as a function of loading and number of cycles. This information is then transferred to the probabilistic fatigue damage analysis procedure for probabilistic forecasting of the damage evolution of the component. Here we report preliminary results obtained by applying this methodology to experimental data.