Model evaluation of HWRF simulations for Hurricane Edouard (2014)

The Hurricane Weather Research and Forecasting Model (HWRF) is one of the National Centers for Environmental Prediction (NCEP)'s operational hurricane models, which has provided real-time numerical guidance to National Hurricane Center (NHC) since 2007. Over the years, its real-time guidance expended globally to all Tropical Cyclone (TC) basins in 2015. Despite HWRF prevalence there are relative few comparisons of the model with observations beyond those based on the best track data. Extensive observational efforts were conducted for the North Atlantic Hurricane Edouard (2014), supported by the FY2013 Sandy Disaster Assistance Supplemental and those made in the context of the Hurricane Severe Storm Sentinel (HS3) field campaign. Multiple research missions by NOAA and NASA collected measurements throughout the storm's lifecycle. The observations include those by the first deployment of the unmanned Aircraft System denominated COYOTE. In this work, we compare model performance using the observation-derived fields. We investigate the rapid intensification (25 kt over 36 hours from 00Z September 15 to 16, 2014) that Edouard went through in nature and that while corresponding HWRF did not match the large intensity change (the model intensity forecasts were weaker by ~30 kt). During this period, the storm moved into a low shear environment. The preliminary results suggest that the strength and location of a warm pool existing at the western part of the North Atlantic subtropical gyre, as well as low vertical wind shear, played an important role in the rapid intensification.