An Analysis of NCEP Tropical Cyclone Vitals and Potential Effects on Forecasting Models

Abstract

his study analyzes the Tropical Cyclone Vitals Database (TCVitals), which contains cyclone location, intensity, and structure information, generated in real time by forecasters. These data are used to initialize cyclones in several NCEP operational forecasting models via bogusing and vortex relocation methods. In many situations, time is of the essence and the TCVitals database represents the best real-time estimate of the cyclone state possible in real time, given the limitations of available data and time constraints inherent in real-time forecasting. NCEP and other users of TCVitals have a responsibility to work around the inevitable limitations of what forecasters can do for TCVitals in real time. With ensemble systems becoming available, a way to do that will soon be available. However, the TCVitals? limitations must first be quantitatively understood so that model developers can take them into account. That is the motivation for the present study, which compares the TCVitals storm location and intensity to postseason reanalysis values found in the best-track database and statistically compares the TCVitals storm depth to 946 Tropical Rainfall Measuring Mission (TRMM) overpasses. All storms of tropical depression strength or stronger in all basins are analyzed, with a special focus on National Hurricane Center TCVitals for the North Atlantic and eastern Pacific basins, the main areas of responsibility for NCEP. In addition, the sensitivity to TCVitals on the Hurricane Weather Research and Forecasting (HWRF) model is examined by rerunning the 2011 HWRF for the 2010 North Atlantic season twice: once with TCVitals input and once with best-track input.