The Weeks 3-4 Program within the NWS Office of Science and Technology Integration (OSTI) Modeling Program Division was established in 2016 as part of an agency-wide initiative to improve extended-range weather outlooks with a 5-year initial funding from Congress. This kick-started activities within two NOAA Line Offices, the National Weather Service (NWS) and the Office of Oceanic and Atmospheric Research (OAR) with the following 4 thrust areas: 

• extending numerical model guidance out in time
• building reforecast and reanalysis capabilities
• innovating forecast products and 
• supporting applied research in the sub-seasonal forecast range.

The Weeks 3-4 Program has supported the development and improvement of weeks 3-4 forecast products at the Climate Prediction Center (CPC) of NCEP and development and implementation of the sub-seasonal  Global Ensemble Forecast System (GEFS) version 12 at the Environmental Modeling Center (EMC) of NCEP in September 2020. The GEFS v12 is a major upgrade since 2015, including FV3 dynamical core, increased forecast length to 35 days, increased model resolution to 25 km and ensemble to 31 members, coupling with waves and aerosol components, and a 30-year reanalysis and reforecast. 

The Weeks 3-4 Program currently supports the development and implementation of GEFS v13, which is currently being developed through the UFS-R2O Project. The program also supports a number of multi-year projects at the NCEP CPC that cover a range of focus areas such as Arctic sea ice prediction, drought monitoring, excessive heat outlooks  and use of machine learning algorithms in weeks 3-4 temperature and precipitation outlooks. 

The Weeks 3-4 Program has close coordination and collaboration with the Subseasonal-to-Seasonal (S2S), Climate Test Bed (CTB), JTTI and EPIC Programs at the Weather Program Office of NOAA Oceanic and Atmospheric Research (OAR) on transitioning research to operations. In addition, it promotes advancement of Earth system model capability, coupled data assimilation, reanalysis and reforecast, S2S diagnostics and evaluation softwares, and S2S forecast product developments with other programs and multi-agency initiatives.

Additionally, the Weeks 3-4 Program solicits competitive research proposals within the NWS OSTI’s NOFO (Notice of Funding Opportunities) that is typically announced every two years.  

Contact information:

Yan Xue (Program Manager) at Yan.Xue@noaa.gov