WRF Release Information

Latest Releases

The latest WRF system major release is Version 3.9 (April 2017), and details on it may be found at WRF V3.9 Model Updates and WRF/WPS/WRFDA Downloads.  Some of V3.9's major improvements are as follows.

  • Dynamics: Hybrid vertical coordinate
  • Software: Physics suite selection mechanism, OpenMP updates, WENO advection speedups
  • Physics: New P3 microphysics scheme, updated Grell-Freitas cumulus scheme, NSSL microphysics updates, Noah-MP LSM coupled with urban models, updates to Thompson aerosol-aware microphysics scheme, and new LSM datasets (crop, groundwater, albedo)
  • WRFDA: 4D-EnVar capability, AMSR2 cloudy radiance obs assimilation, null-echo radar obs assimilation, updated CRTM (V2.2.3)
  • WRF-Chem: New TUV photolysis scheme, wet removal in MOZCART
  • WRF-Hydro: Multiple time scale capability, new level pool scheme, new bucket model, netcdf output for baseflow bucket model
  • HWRF: Addition of 2016 operational system changes, new scale-aware SAS scheme, idealized TC capability

The most recent WRF releases are minor releases V3.9.1 and V3.9.1.1.  These were issued in August 2017 and among other things provided a revised version of WPS and bugfixes to V3.9.

  • WRF-Chem: Added RACM_SOA_VBS_AQCHEM_KPP chemical mechanism to the call to the optical driver in order to calculate/output aerosol optical properties.

Upcoming Release

The next major WRF release will be Version 4.0 and is targeted for Spring 2018. This will have the hybrid vertical coordinate as the default, and the new version will not be backward-compatible with all components of previous versions. A list of candidate features for the release will be compiled in Fall 2017, with the ultimate inclusion of any candidate item dependent on its timely preparation and final acceptance. The general timeline for the release is given below.

Developers seeking to propose code for new or improved capabilities for the WRF system must review Information for Code Contributors. The consideration of any code for the WRF repository or a release depends on the developer's following the physics review procedures, meeting testing.preparation, and documentation requirements, and adhering to the release schedule. Prospective contributors may write to wrfhelp@ucar.edu for information and for contacting the Developers' Committee (which oversees WRF contributions and manages the repository) or the Release Committee (which oversees the major release process). Both the Developers' Committee and the Release Committee are described in WRF Code Repository and Release Administration.

Timeline— 2018 WRF Major Release

The timeline for the next major WRF release, scheduled for Spring 2018, is as follows. "RC" refers to the Release Committee; "DC" refers to the Developers' Committee.

September 2017

  • RC begins meetings for major release cycle.
  • Initial release picture compiled and schedule set.

December 2017

Code accepted and admitted to the repository is eligible (but not guaranteed) to be included in the release. Code submissions must undergo all preliminary testing and acceptance by the end of December in order to be considered for the release. A release branch of the code will then be identified and will be the basis for the release code. While the WRF repository will remain open to submissions after this time (as the repository is open throughout the year), new additions will not be eligible for the release branch.

January 2018

Release code testing and first friendly-use release

  • Only bugfixes for preliminary release code permitted.
  • WRF repository remains open for code additions, which may be considered for releases after the 2017 major release.
  • First friendly-user release— preliminary code made available for testing.

Late February 2018

Continued release code testing and second friendly-use release

  • Remaining bug fixes implemented.
  • Full set of regression tests run on machines at NCAR.

March 2018

  • Final round of troubleshooting and large testing.
  • RC and DC meetings focus on remaining code needs and testing. Final commit schedule and preparation determined.

April 2018

  • DC certifies code (final approval) for release. Code packaged and staged for release.
  • Release and notification to WRF users.

Release Committee

The WRF Release Committee oversees the major releases of WRF. It is described in the policies for NCAR's administration of the WRF code in WRF Code Repository and Release Administration. The members are listed below.

Jordan Powers, NCAR/MMM— Chairman
Ravan Ahmadov, NOAA/ESRL
Michael Barlage, NCAR/RAL
Mrinal Biswas, DTC
Laurie Carson, DTC
Jimy Dudhia, NCAR/MMM
Dave Gill, NCAR/MMM
Michael Kavulich, NCAR/MMM
Steven Peckham, CRREL
Wei Wang, NCAR/MMM