Evaluation of GFDL fvGFS Quantitative Precipitation Forecasts for 2017 US-Landfalling Tropical Cyclones

There were three high-impact hurricanes (Harvey, Irma, and Maria) in 2017 that caused unprecedented rainfall, catastrophic flooding, and loss of life in the United States. In this paper, we evaluate the skill of the Geophysical Fluid Dynamics Laboratory (GFDL) finite-volume Global Forecast System (fvGFS) in quantitative precipitation forecasts for US-landfalling tropical cyclones in 2017. Qualitative comparisons to observations of two fvGFS configurations, 13-km global and 3-km nested, will highlight the capability of these modeling systems to produce rainfall and flood guidance. Results from the fvGFS configurations will be compared against contemporary operational models, including the GFS, NAM, and HWRF.