The object of the study is to model the electromagnetic scattering by time-evolving sea surfaces illuminated by high frequency surface wave radars. A common way to simulate this case is to consider the scattering at grazing incidence. Recent studies have focused on so-called exact methods. As such methods are very time and memory consuming, it becomes important to implement techniques to reduce the calculation costs. Another important issue is to better understand the interactions between the electromagnetic waves and moving sea surfaces. We present in this article our simulator main characteristics and a comparison between simulated data and measurements.