Seasonal prediction skill in a coupled climate model system largely depends on the E1 Ni(n)o/Southern Oscillation (ENSO) prediction skill.In summer of 2012, there was a clear signal of developing E1 Ni(n)o over the equatorial Pacific and many models forecasted El Ni(n)o occurrence with a peak phase in the subsequent winter.However, the warming was aborted abruptly in September.In this study, we show that the abrupt termination of the 2012 Pacific warming was largely attributed to the anomalous sea surface temperature (SST) cooling in the northeastern subtropical Pacific.The anomalous SST cooling induced strong easterly and low-level divergence anomalies, suppressing the development of westerly and convection anomalies over the equatorial central Pacific.Thus, the warming over the equatorial Pacific was decoupled from the wind and subsurface thermocline variability, inhibiting its further development into a mature E1 Ni(n)o in the winter of 2012-2013.This study highlights the importance of the SST anomaly in the northeastern subtropical Pacific in E1 Ni(n)o prediction.