Evaluating the performance of various lead-time indicators in anticipating the high impact 2017 Atlantic hurricane season

The 2017 Atlantic hurricane season will long be remembered as one of the most active on record. After several quiet years, the notion of an active season became increasingly apparent as the official Atlantic season (June-November) approached. In this study, a successful statistical model forecast from late April is examined in order to determine the strongest contributing factors that were anticipated in the forecast from a suite of variables, including accumulated cyclone energy, sea surface temperature (SST), vertical wind shear, column water vapor, and mean sea-level pressure. Each of these variables as forecasted supported the case for elevated tropical cyclone activity in 2017 to some extent with the possible exception of vertical wind shear. The roles of various teleconnections, including the Madden-Julian Oscillation, El Niño Southern Oscillation (ENSO), Atlantic Multi-decadal Oscillation (AMO), Indian Ocean Dipole, and others in anticipating the favorable conditions for tropical cyclone activity are also analyzed. Some relationships such as the one between ENSO and seasonal vertical wind shear as well as seasonal SST and AMO are well-known, but other relationships between teleconnections and seasonal variables that are not as well established proved to be critical in correctly anticipating the very active 2017 hurricane season.