The Operational Challenges of Forecasting TC Intensity Change in the Presence of Dry Air and Strong Vertical Shear

Tropical cyclone intensity changes involve a complex interplay of many factors including vertical wind shear and the thermodynamic properties of the ambient atmosphere and ocean. While the individual effects of vertical shear and dry air intrusion on tropical cyclones have been well established, much less emphasis has been given to the combined effects of these two environmental influences working in tandem. This study offers a conceptual depiction of how dry air intrusion and vertical shear work together by analyzing kinematic and thermodynamic cross-sections from dynamical models, dropwindsonde data, and satellite data. We further examine, from an operational perspective, previously published hypotheses that strongly sheared cyclones are more susceptible to dry air entrainment than weakly sheared cyclones. Additionally, we analyze the performance of the Statistical Hurricane Intensity Prediction Scheme (SHIPS) in cases with and without these factors working in tandem.