Topic 2.0: Tropical cyclone formation and extratropical transition

Abstract

In this section, progress since ITWC-VI on research, observations and forecasting of tropical cyclone formation and extratropical transition is summarized. While tropical cyclone formation and extratropical transition are stages at opposite ends of the tropical cyclone lifecycle, significant lack of understanding remains in relation to processes associated with each stage. Formation and extratropical transition involve interactions among physical processes that vary over multiple space and time scales. Additional, relatively few, consistent in situ observations of each stage exist. Tropical cyclone formation often occurs over remote regions that do not contain standard observation capabilities or are out of range of tropical cyclone observation program assets. While extratropoical transition may occur downstream from data rich continental regions, the stage is rarely targeted for in situ observations as the storm is no longer a landfall threat.