2.4 Hurricane WRF: 2017 operational implementation and community support.

Liu, Bin, IMSG Inc. and National Oceanic and Atmospheric Administration (NOAA)/Environmental Modeling Center (EMC), Avichal Mehra, NOAA/EMC, Zhan Zhang, IMSG Inc. and NOAA/EMC, Kathryn Newman, National Center for Atmospheric Research (NCAR), Sergio Abarca, IMSG Inc. and NOAA/EMC, Ligia Bernardet, NOAA/Global Systems Division (GSD) and Cooperative Institute for Research in Environmental Sciences (CIRES), Mrinal Biswas, Laurie Carson, NCAR, Jili Dong, IMSG Inc. and NOAA/EMC, James Frimel, NOAA/GSD and Cooperative Institute for Research in the Atmosphere, Evelyn Grell, NOAA/Physical Sciences Division and CIRES, Evan Kalina, NOAA/GSD and CIRES, Hyun-Sook Kim, IMSG Inc. and NOAA/EMC, Qingfu Liu, NOAA/EMC, Tim Marchok, NOAA/Geophysical Fluid Dynamics Laboratory, Zaizhong Ma IMSG Inc. and NOAA/EMC, Jessica Meixner, Dmitry Sheinin, IMSG Inc. and NOAA/EMC, Jason Sippel, NOAA/Hurricane Research Division, Biju Thomas, University of Rhode Island, Mingjing Tong, Weiguo Wang, Keqin Wu, Banglin. Zhang, Lin Zhu, IMSG Inc. and NOAA/EMC, and Vijay Tallapragada, NOAA/EMC

The Hurricane WRF model (HWRF) is one of the various applications of the WRF model in NWS/NCEP operations, providing real-time forecasting for all global tropical cyclones (http://www.emc.ncep.noaa.gov/HWRF). Its main customers include the National Hurricane Center, Central Pacific Hurricane Center, and Joint Typhoon Warning Center, which use HWRF as numerical guidance for tropical cyclone forecasting. Furthermore, HWRF is also run across the globe by other countries' forecast centers, and by research groups. HWRF is an air-sea coupled hurricane forecasting system, with sophisticated vortex initialization and advanced data assimilation (DA) processes, as well as post-processing (Unified Post-Processor) and vortex tracking (GFDL Vortex Tracker) processes. Since 2016, operational HWRF also provides hurricane sea surface wave forecasts by including the one-way coupling capability to the WaveWatch III model component. In this work, a summary of the upgrades and configuration for the FY2017 operational HWRF implementation will be reported, including the system and framework enhancements, initialization and DA improvements, as well as physics advancements. Results from three-year retrospective tests show that the combined impact of increased vertical levels, updated physics (e.g. the scale-aware SAS convection and the Ferrier-Aligo microphysics schemes), and DA advancements, lead to better track and intensity forecasting, with substantially improved storm size and structure. Additionally, an overview of the HWRF community support that is provided by the Developmental Testbed Center (http://www.dtcenter.org/HurrWRF/users) will be discussed.