Secular changes to the ENSO-US hurricane relationship

Analysis of the statistical relationship between annual U.S. hurricane activity and the El Nino-Southern oscillation (ENSO) is performed. The legitimacy of considering annual U.S. hurricane counts as a Poisson process is checked. Then, Poisson regression is used to model the ENSO-U.S. hurricane connection. A bivariate regression model verifies a significant negative correspondence between tropical Pacific sea-surface temperature (SST) and U.S. hurricane activity. When equatorial SSTs are cold, U.S. hurricanes are more likely. Secular changes to the ENSO-U.S. hurricane relationship are examined using moving regressions. A nonlinear downward trend in the relationship's strength is evident. Variations in sea-level pressures over the extra-tropical North Atlantic Ocean during months immediately prior to the hurricane season provide an explanation for a portion of this secular variability. Atmospheric synoptic conditions associated with the North Atlantic oscillation (NAO) result in hurricanes tracking parallel to southern latitudes en route to the United States.