Quantifying the onset of extra-tropical transition using four-dimensional analysis techniques

There were over five hundred named tropical cyclones in the last fifty years over the north Atlantic basin, and over two hundred of those systems were determined to have undergone extra-tropical transition, according to the National Hurricane Center. Transitioning cyclones can produce severe weather including heavy precipitation and high winds. In this study, four-dimensional visual analytic techniques are used to evaluate the meteorological characteristics of tropical cyclone cores to determine the time and mechanisms associated with extra-tropical transition. A total of 51 named tropical cyclones transitioned after making landfall in the United States between 1979 and 2008. For each of these systems, North American Regional Reanalysis (NARR) data were used as input into the Weather Research and Forecasting (WRF) model to generate high resolution gridded data for subsequent analysis. Analysis was done using ParaView, a four-dimensional visualization application that was developed for the visualization of large scientific datasets. Results show that four-dimensional visualization techniques allow for enhanced analysis of the conditions associated with tropical cyclone transitions, leading to earlier detection of transition by improving the identification of the development of a system's cold core. Four-dimensional analytic techniques have led to an improvement in the recognition of the onset of tropical cyclone transition compared to National Hurricane Center estimates, due to the ability to analyze continuous vertical and horizontal atmospheric properties.