1. 1 Seasonal to Interannual multi-model approach Presented By: Jin Huang (NWS/NCEP/CTB) Contributors: Yuejian Zhu (NWS/NCEP/EMC)

2. 2 Operational System Attribute(s) System NameAcronymAreal Coverage Horz ResCycle Freq Fcst Length North American Multi-Model Ensemble NMMEGlobal1x1Once a month 9 months NMME Seasonal Forecast System Description

3. 3 Why System(s) are Operational  Primary stakeholders and requirement drivers NCEP/Climate Prediction Center (CPC) ESPC, NCEP Internal Desk, and private sectors  What products are the models contributing to? NMME monthly and seasonal forecasts for SST, Precip, and T2m.  What product aspects are you trying to improve with your development plans? Forecast skill, probabilistic forecasts, forecast reliability and uncertainty estimates  Top 3 System Performance Strengths Improved forecast skills, reliability, probabilistic distribution and uncertainty estimate Leveraging advances of external model development Involving the external community in real-time forecasts and diagnosis  Top 3 System Performance Challenges Commitment from NASA and DOE in the operational NMME The operational system is supported for 3 years (to July 2018) only NWS acceptance of a distributed system as an operational system

4. 4 System Evolution Over the Next 5 Years  Major forcing factors Improved NMME seasonal forecast products for CPC operation Weeks 3-4 forecasts to fill the gap in MME forecast products for NCEP and ESPC  Science and development priorities Upgrade the participating model systems Apply more advanced merging technique to combine models Test NMME sub-seasonal forecast system  What are your top challenges to evolving the system(s) to meet stakeholder requirements? More direct Influence on development/improvement of individual participating model systems including initialization strategy Effort for systematic testing and evaluation of system upgrades  Potential opportunities for simplification going forward The signed agreement allows the NMME system to get model upgrades from participating modeling centers. Both weather community and seasonal forecast community are interested in developing sub-seasonal forecasts.

5. 5 Top 3 Things You Need From the UMAC 1. Can and how the NMME seasonal forecast system be sustained after July 2018? 2.What is the best approach for a sub-seasonal MME system? Can the future NMME sub- seasonal system continue to be distributed? 3. Should NOAA invest more effort to make the NMME data more user-friendly, such as, like S2S data?