A dominant mode of interannual climate variability over the tropical Atlantic, North tropical Atlantic variability (NTA), has been traditionally characterized by a single pattern of basin-scale sea surface temperature (SST) anomalies spanning from the equator to the subtropical North Atlantic, with substantial impacts on Atlantic hurricane activity. The period 2023-2024 saw two consecutive strong NTA warm events but with distinct anomaly patterns. The 2024 BNTA event fueled an extreme Atlantic hurricane season – including the earliest-formed category-5 hurricane (Beryl) and second-deadliest landfalling hurricane (Helene), resulting in an economic damage and loss of lives far greater than in 2023. Here we use observations and model outputs to find that there exists inherent diversity in NTA SST spatial structures and impacts. Two distinctive modes of variability: a basin-wide mode and a coastal mode, are underpinned by differing local air-sea interaction and oceanic feedback. The basin-wide mode has a stronger influence on Atlantic hurricane activity due to its more westward and persistent anomaly pattern. Extreme Atlantic hurricane seasons, as seen in 2024, likely occur more frequently due to the shifting NTA SST patterns under global warming.

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