A summary of recent GFDL model upgrades and plans for 2006

Since 1995 the GFDL Hurricane Prediction System has provided operational guidance for forecasters at TPC in both the Atlantic and East Pacific ocean basins. With the installation of a new generation computer at the National Centers for Environmental Prediction (NCEP), the computer power available for operational models was significantly increased in 2005, enabling major upgrades to the GFDL hurricane forecast system to be made. Most significant was a doubling of the finest resolution which has lead to a much better representation of the hurricane inner core.

Overall, the upgraded hurricane model performed very well throughout the record 2005 hurricane season. A brief summary of the track and intensity forecasts in both basins will be presented.

During the past year further upgrades to the model physics have been developed and are currently being tested. Coupling of the GFDL forecast model with the NCEP Wavewatch model has been successfully made, to more accurately predict the momentum fluxes at the surface. This has lead to much better prediction of the magnitude and distribution of the surface winds. A new version of the model's moist physics utilizing the NCEP Ferrier micro-physics is currently being evaluated on cases during the 2005 hurricane season. Preliminary results continue to indicate that this physics improvement is leading to significantly better intensity forecasts in sheared situations. Examples of the effect of these two major physics improvements in GFDL forecasts from the 2005 season will be shown as well as a summary of the improved track and intensity forecasts for the cases tested. Some of the other additional minor changes to the model planned for 2006 will also be discussed.