Tropical cyclones and the environment in which they grow in the NCEP Climate Forecast System

In August 2004, NCEP implemented a Climate Forecast System (CFS) which provides an ensemble of forecasts to nine months using a coupled climate model together with a data assimilation systems of the atmosphere and the ocean to provide initial conditions. The CFS has been shown to have skill in the predictions of the equatorial Pacific Sea Surface Temperature and the ENSO events. Since the atmospheric component of the CFS model is the operational Global Forecast System (GFS) model circa 2003 which is known to exhibit tropical cyclone genesis in the forecast mode, it is of interest to examine the tropical cyclones in the CFS in a fully coupled model mode for seasonal predictions. We will examine the model simulations of tropical cyclones in the CFS and compare the statistics with observations. In addition, we will also examine the model environment (vertical wind shear, sea surface temperature) and their relationship to the tropical cyclones on the seasonal time scale.