While the North Atlantic tropical basin continued the near-normal activity seen in 2006, the Eastern Pacific and Western Pacific tropical basins both experienced dramatically below normal TC activity in 2007 under a variety of metrics. Nevertheless, even in a year of relative inactivity, significant events occurred including rapid intensification episodes, two consecutive Caribbean Category 5 hurricanes (Dean and Felix), as well as Gonu and Sidr, two Category 5 Northern Indian Ocean cyclones.
Against a backdrop of global warming and the conjectured effects it may have on tropical cyclones, 2007 (and 2006) provided a definite respite from the enhanced activity of the 1990s and 2004 and 2005 -- on a hemispheric scale. Of the many factors potentially responsible, the transition from weak El Nino to La Nina conditions during the heart of the TC season seems to be a likely candidate for enhanced vertical wind shear in the main development corridors. Recent work by the authors indicates that the anomalous summer/fall TC inactivity could portend an equally anomalous winter season of 2007/2008, given the dramatically reduced workload performed by TC's in 2007.