  The numerical simulation of the nonlinear dynamics of random sea waves at
moderately small Benjamin-Feir indices and its comparison with the linear
dynamics (at the coincidence of spatial Fourier harmonics near a spectral peak
at a certain time $t_p$) indicate that the appearance of a rogue wave can be
predicted in advance. If the linear approximation shows the presence of a
sufficiently extensive and/or high group of waves in the near future after
$t_p$, an anomalous wave is almost necessarily formed in the nonlinear model.
The interval of reliable forecasting covers several hundred wave periods, which
can be quite sufficient in practice for, e.g., avoiding the meeting of a ship
with a giant wave.
