Sixth International Workshop on Tropical Cyclones Topic 2 : Tropical Cyclone Formation and Extratropical Transition External Influences on Formation

In this section, summaries of recent progress in observations, forecasting, and research of tropical cyclone formation and extratropical transition are provided. Furthermore, requirements that remain for advancements in these topics are identified. During the period since IWTC-V, there have been improvements in observational capability, new research results into important physical processes, and forecast improvements with respect to tropical cyclone formation and extratropical transition. However, further requirements have also been identified. A partial list of these requirements includes improved definitions of formation and extratropical transition, validating theories of tropical cyclone formation, identifying the role(s) of the large-scale environment in tropical cyclone formation and extratropical transition, sensitivities in formation and extratropical transition to important physical processes, and the impact of an extratropical transition event on the downstream midlatitude circulation.