Impacts of mid-latitude SST variability on the Atlantic Meridional Mode

Recent research has demonstrated that the Atlantic Meridional Mode (AMM) is predictable up to one year in advance. Currently, the source of that predictability, including the dynamical evolution of anomalies that develop into the AMM, is not well known. A positive phase of the AMM is shown to reduce shear in the main development region (MDR) of hurricane formation during the climatological peak of hurricane season.

Global circulation model (GCM) experiments have confirmed the emergence of the AMM after being initialized with a mid-latitude SST anomaly. These results were corroborated by a linear inverse model, which showed a spatially coherent structure similar to the GCM results. Given the relationship between decreased shear and increased hurricane activity, these results can potentially be used to predict seasonal hurricane activity up to a year in advance.