Planetary-Scale Low-Level Circulation and the Unique Development of Hurricane Wilma in 2005

Large‐scale atmospheric and oceanic conditions in the western Atlantic basin were analyzed to understand the unique tropical cyclogenesis (TCG) and intensification mechanism of Hurricane Wilma in 2005, the most intense Atlantic basin tropical cyclone (TC) on record. An analysis of 850 hPa circulations depicted in the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data suggests that anomalous development of the 850 hPa circulation pattern triggered by Hurricane Vince (October 8–11, 2005) contributed to the development of a large‐scale low‐level vortex that preceded Wilma\u27s TCG in the eastern Caribbean. In particular, weakened easterly winds in the central tropical Atlantic assisted the unique large‐scale cyclonic circulation over the western Atlantic about a week before Wilma\u27s TCG. The unprecedented rapid intensification of Wilma was investigated considering the interactions between mid‐latitude troughs and large‐scale low‐level circulations as well as anomalously warm SST conditions. The global Weather Research and Forecasting (WRF) model run for Hurricane Wilma suggests that the role of mid‐latitude systems in TC activity is more important than previously believed and that every in situ large‐ or meso‐scale vortex and circulation component at least in the immediately neighboring region of TCG seems to have a significant influence on TCG processes