Central Pacific El Niño-driven Pacific–Atlantic teleconnections are an important source of North Atlantic Oscillation predictability

Abstract The wintertime North Atlantic Oscillation is a major mode of variability affecting climate across the Northern Hemisphere, yet its seasonal prediction skill over the North Atlantic remains lower than that over the Pacific. We examine North Atlantic Oscillation predictability through Pacific teleconnections using reanalysis data and multi-model hindcasts from seasonal-to-decadal forecasting systems. Here we show that Central Pacific El Niño events significantly enhance both North Atlantic Oscillation forecast skill and the predictable signal over the North Atlantic. Reanalysis and equatorial Pacific pacemaker experiments reveal that Central Pacific El Niño enhances sea surface temperature variability over the Aleutian region, modulates Atlantic storm-track activity, and strengthens the Pacific–Atlantic teleconnection. Coupled Model Intercomparison Project Phase 6 simulations suggest that more frequent Central Pacific El Niño occurrence under greenhouse warming may favor this teleconnection. These results identify Central Pacific El Niño-driven Pacific–Atlantic teleconnections as an important source of North Atlantic Oscillation predictability and seasonal forecast skill.