Large-scale characteristics of rapidly intensifying tropical cyclones in the North Atlantic Basin

An analysis of recent operational Atlantic basin tropical cyclone forecasts issued by the National Hurricane Center indicates that tropical cyclone intensity forecasting has proven to be less skillful than has tropical cyclone track prediction. Moreover, the forecasting of rapid intensity change has proven to be especially difficult as was underscored by the failure of operational models to adequately predict the rapid intensification of Hurricanes Opal (1995) and Bret (1999).

In this study, data obtained from the SHIPS database for the period from 1989-1998 will be utilized to identify the large-scale conditions that appear to be conducive to rapid intensification. This will be accomplished by evaluating the magnitude of various synoptic variables (e.g, vertical shear, relative-eddy angular momentum fluxes) that were present at the start of each period of rapid intensification to determine if these conditions were significantly different from those associated with storms whose rates of intensification were much less rapid. In addition, data collected by the Hurricane Research Division during the 1999 hurricane season may also be employed to determine if the statistical results obtained by analyzing the SHIPS database can be confirmed by more detailed case studies.