Unified Forecast Information

UNIFIED FORECAST SYSTEM

 

The Unified Forecast System (UFS) is a community-based, coupled comprehensive Earth system modeling system.  The UFS numerical applications span local to global domains and predictive time scales from sub-hourly analyses to seasonal predictions.  It is designed to support the Weather Enterprise and to be the source system for NOAA's operational numerical weather prediction applications.

For more details and current UFS events, please go to the UFS Community Web Portal at https://ufscommunity.org/

1. Background

In 2014 as part of the NWS’s Research to Operations (R2O) 5 year plan, the current operational Global Forecast System (GFS) will be upgraded to run as a unified, fully coupled Next Generation Global Prediction System (NGGPS) within the NEMS (NOAA Environmental Modeling System) infrastructure. Using advanced high performance computing architectures, the system will incorporate the most recent advances in weather prediction modeling from NOAA and the research community.

  • Implement a weather-scale, fully-coupled NWP System
  • Extend forecast skill beyond 8 to 10 days
  • Improve hurricane track and intensity forecast
  • Extend weather forecasting to 30 days

 

During 2014, NOAA initiated the evaluation process for five potential candidate dynamical cores to serve as the foundation for the NGGPS:

  1. Global Non-hydrostatic Mesoscale Model (NMM & NMM-UJ) - EMC
  2. Model for Prediction Across Scales (MPAS) - NCAR
  3. Non-hydrostatic Icosohedral Model (NIM) - ESRL
  4. Navy Environmental Prediction System Using the NUMA Core (NEPTUNE) - Navy
  5. Finite Volume Model version3 - (FV3) - GFDL

 

After an extensive evaluation process, the Finite-Volume on a Cubed-Sphere (FV3) dynamic core was chosen in the summer of 2016. The FV3 core, developed at NOAA’s Geophysical Fluid Dynamics Laboratory, brings a new level of accuracy and numeric efficiency to the model’s representation of atmospheric processes such as air motions. This makes possible simulations of clouds and storms, at resolutions not yet used in an operational global model.

The FV3 core enables the model to provide localized forecasts for several weather events simultaneously all while generating a global forecast every six hours. Looking 10 years ahead, the GFS model with the FV3 core will run in higher resolution and be able to zoom in on smaller and smaller storm systems to provide forecasters better pictures of how storms will evolve.

Goals for the new model are:

  • a unified system to improve forecast accuracy beyond 8 to 10 days
  • better model forecasts of hurricane track and intensity, and
  • the extension of weather forecasting through 14 days and for extreme events, 3 to 4 weeks in advance.

 

Engaging the meteorology community during model development and improvement is a priority for NOAA. The agency plans to develop a program to involve researchers in testing and improving algorithms, data assimilation methods and physics. The goal is to incorporate successful enhancements into operations. 

 

2. Near-term UFS plans / current developments at EMC

The implementation of the FV3GFS (GFS v15) into NCEP’s operational model suite was accomplished on June 12, 2019. This version of the FV3GFS will run the existing GFS v14 physics suite with the GFDL microphysics scheme replacing the previously operational Zhao-Carr scheme. Further details on the changes to the global forecast and hybrid data assimilation system accompanying this implementation can be found in Official Science and Decision Brief to the NCEP Director.

With the initial operational implementation of FV3GFS now accomplished, EMC's global modeling focus has turned towards development of the next GFS (v16) upgrade, which will include doubled vertical resolution (64 to 127 layers), more advanced physics, data assimilation system upgrades, and coupling to a NCEP Global Wave Model. Implementation of GFSv16 is targeted for the early winter of 2021.

On 23 September 2020, the global UFS application at NCEP was implemented in the Global Ensemble Forecast System (GEFS v12). The components of this upgrade include: 

  • Use of the FV3 global model (same version as GFS v15) as the atmospheric component of GEFS
  • Increase in horizontal resolution to ~25 km
  • Forecast length increased from 10 to 16 days
  • Increased from 21 to 31 members
  • Coupling the GEFS atmospheric component to the NCEP Global Wave model
  • Run a 32nd member to 5 days (GEFS-Aero) for aerosol prediction, inline aerosol representation based on GOCART (GSD-Chem).

This implementation is the first global-scale coupled system at NCEP, and replaces the previous standalone Global Wave Ensemble and the NEMS GFS Aerosol Component (NGAC) systems. More details can be found at the EMC Model Evaluation Group’s GEFS v12 web site, the EMC GEFS web page, and the EMC GEFS-Aerosol web page.

Concurrently, a collaborative effort between EMC, ESRL/GSD, NSSL, and GFDL is underway to develop and test a FV3 limited-area regional model (FV3-LAM) at convective-allowing model (CAM) horizontal resolution of ~3 km. EMC's short-term goal is to replace the NEMS-NMMB member of the operational High-Resolution Ensemble Forecast (HREF) system with an FV3-SAR member, scheduled for the winter of 2020. The long-term goal is to replace NCEP’s current suite of high-resolution guidance (HRRR, HREF, NAM nests) with an FV3-based Rapidly Refreshed Forecast System (RRFS) by 2023.