Software Release: Release v3.9a of the HWRF system

Proposals for Contributions Encouraged

The Developmental Testbed Center (DTC) is pleased to announce the release of version 3.9a of the community HWRF modeling system. The release includes all components of the system: scripts, data preprocessing, vortex initialization, data assimilation, atmospheric and ocean models, coupler, postprocessor, and vortex tracker. Both the Scientific Documentation and the Users Guide have been updated.

Users may go to to download codes, acquire datasets, and get information and documentation about HWRF.

The upgrades in version 3.9a are listed below:

  • Compatible with the 2017 operational HWRF.

  • WRF upgraded to v3.9.1 and GSI to v3.6.

  • D02 and D03 domain size decreased to ~ 24x24 degrees and ~ 7x7 degrees respectively.

  • Number of vertical levels increased to 75 with a model top of 10 hPa for the AL, EP, and CP basins and to 61 with a model top of 10 hPa for the WP basin and NIO.

  • Miscellaneous upgrades and bug fixes in various physical parameterizations.

    • Updated Scale Aware Simplified Arakawa Shubert scheme for cumulus parameterization.

    • Updated GFS Hybrid-Eddy Diffusivity Mass Flux PBL scheme.

    • Updated Ferrier-Aligo microphysics scheme.

    • Updated momentum and enthalpy exchange coefficients (Cd/Ch) in surface layer parameterization.

    • Updated partial cloudiness scheme for RRTMG.

  • Ocean upgrades

    • Reduced coupling time step from 9 min to 6 min for ocean coupling.

    • Increased vortex tracking frequency.

    • Number of vertical levels in MPIPOM-TC increased from 24 to 41.

  • Initialization upgrades

    • Use of a new composite storm vortex for improved vortex initialization.

    • Assimilating new data sets with GSI (hourly Atmospheric Motion Vectors /AMV/, clear-water-vapor AMV's).

  • New version of GFDL vortex tracker

For questions and inquires, contact

The DTC would like to encourage prospective contributors to apply to the DTC visitor program for transitioning research to the operational HWRF system. Proposals are accepted year-around. Please check the visitor program webpage ( for the latest announcement of opportunity and application procedure.