Additional analysis of major hurricane landfall activity yields that the important relationship between El Niño Southern Oscillation (ENSO) and landfall is largely dependent on Atlantic Multidecadel Oscillation (AMO). It was noted that during negative AMO phases, there is a clear negative correlation between ENSO and MHL frequency (r < -.6), whereas there is no noticeable correlation during positive AMO phases. This indicates that AMO can largely influence the empirical interannuel relation between ENSO and tropical cyclone landfall frequency. However, during AMO positive phases, the correlation between all storm landfall (ASL) and MHL remains strong (r > 0.6). This strong correlation illustrates that the physical mechanism controlling the relationship between ASL and AMO during positive phases is key to understand the variations in the MHL activity.
Because the most recent 12-year major hurricane landfall drought took place during an AMO positive phase, the MHL and ASL frequencies were compared to other notable AMO positive decades (1930-1940 and 1950-1960) to deem the landfall activity during this drought significant. The ASL and MHL frequencies were found statistically significant (p < 0.05 with a one tailed t- test). Current research is being conducted to compare the drought years to the active 2017 hurricane season and other AMO positive years. Conditions being examined include sea surface temperature, steering flow, and vertical wind shear.