Using a low-dimensional adjoint to the Zebiak-Cane model for ENSO prediction, we find forecast trajectories that reproduce the 1997 and 2002 El Ninos. Taking points on these phase space trajectories 6, 9 and 12 months prior to the events as the forecast initial conditions results, by construction, in excelled "prediction" of these events.

We construct measures of predictability for these events by calculating the stability of these trajectories. We comment on the implications of our results for the debate as to the importance of westerly wind bursts for the outsized El Nino of 1997.