The transition from a tropical cyclone into an extratropical cyclone occurs worldwide several times per year. This so-called extratropical transition is often associated with high impact weather. At the same time the complexity of the structural changes makes it difficult for models to adequately forecast the development.
In September 2008, Typhoon Sinlaku moved along the coast of Japan and re-intensified as a tropical cyclone shortly before it underwent extratropical transition. The structural changes of this typhoon are analyzed based on a unique measurement dataset and simulations from a numerical weather prediction model. Besides, several meteorological tools are used to analyze the dynamical processes that caused the structural changes of Sinlaku.