Unified Forecast System (UFS) Sub-seasonal to Seasonal (S2S) Application Team (AT)

The UFS Sub-seasonal to Seasonal (S2S) Application Team (AT) is a growing community of researchers, model developers, evaluators and forecasters that work together to build, evaluate and implement the next version of the UFS coupled modeling system for S2S forecasting. The UFS S2S Application will be a state-of-the art modeling system that will not only be used for operational forecasts at the National Weather Service (NWS) National Centers for Environmental Prediction (NCEP) but also for research purposes by wider research and academic communities. The focus of the UFS S2S Application Team is on predictive time scales two weeks to one year. 

The AT’s key objectives are to:

1. collect and prioritize forecast objectives working  with NWS forecasters and model users in general 
2. establish scientific goals for the model development and ensure that they meet the NWS forecast priorities 
3. and to promote or conduct model evaluations and comparisons in order to stay abreast on model performance and deficiencies 

Relevant Models 

The Global Ensemble Forecast System Version 12 (GEFSv12) is the current operational global model that issues subseasonal forecasts at the National Weather Service (NWS) National Centers for Environmental Prediction (NCEP). The GEFS v12, which became operational in September 2020 at the NCEP’s Environmental Modeling Center (EMC) is a major upgrade since 2015, that includes an FV3 dynamical core, increased forecast length (35 days), model resolution (25 km) and ensemble size (31) and coupling with waves and aerosol components, and a 30-year reanalysis and reforecast. 

The next GEFS upgrade (v13), (also referred to as Unified Forecast System (UFS) Medium Range Weather/Subseasonal to Seasonal (MRW/S2S) application) will be a coupled atmosphere-land-ocean-sea ice-wave-aerosol model that is slated for operational implementation in 2024.

Climate Forecast System Version 2 (CFSv2) is another operational model relevant in this time scale. It is currently run for seasonal forecasts. The CFSv2 is a fully coupled model representing the interaction between the Earth's atmosphere, oceans, land and sea ice, that has been operational since 2011.

UFS S2S AT All-Hands Meetings

The S2S Application Team is joining efforts with the EMC Coupled Model Evaluation Team in organizing monthly All-Hands meetings on UFS Coupled Global Model Evaluation on S2S Time Scales. Meetings  will be organized around S2S science topics, including prediction skill of the UFS and other models on this timescale, and new diagnostics designed to advance the understanding of Earth system variability of the S2S timescale. Please see below for upcoming meeting  details and list of past presentations. Another goal of these meetings is to identify projects that can be spun up to fill the gap in the model evaluation, improving the forecast skill, and how to communicate and apply the S2S forecasts.The format of the meetings will alternate between informal presentations followed by short discussions and informal discussions around topics of interest identified by the UFS S2S community. 

Getting involved

To join the UFS S2S AT All-Hands Meeting and subscribe to the UFS S2S AT mailing list please sign up here. If you are also interested in becoming a member of the UFS S2S Application Team, please email UFS S2S AT Co-Lead,  Dr. Cristiana Stan (cstan@gmu.edu).