The Atlantic meridional mode: predictability, dynamics, and impacts on tropical cyclones

The Atlantic Meridional Mode (AMM) is a dominant source of coupled ocean - atmosphere variability in the Atlantic. Recent research has identified the AMM as a major contributor to tropical cyclone activity in the Atlantic. This presentation will review the relationship between the AMM and tropical cyclone activity, as well as the AMM's predictability.

The AMM's strong influence on hurricane activity results from it's relationship to a number of conditions that cooperate on their influence on hurricane activity. The dynamics of these relationships, especially the relationship between sea surface temperature and vertical wind shear, is explored in the observed record and in general circulation model experiments. The AMM has been shown to be predictable out to a year in advance (from the middle of the previous hurricane season). The source of this predictability is explored using empirical and numerical models. Implications for predictability of tropical cyclone activity will be discussed.