A Decade of the North American Multimodel Ensemble (NMME) Research, Application, and Future Directions

Ten years, 16 fully coupled global models, and hundreds of research papers later, the North American Multimodel Ensemble (NMME) monthly-to-seasonal prediction system is looking ahead to its second decade. The NMME comprises both real-time, initialized predictions and a substantial research database; both retrospective and real-time forecasts are archived and freely available for research and development. Many U.S.-based and international entities, both private and public, use NMME data for regional or otherwise tailored forecasts. The system's built-in evolution, with new models gradually replacing older ones, has been demonstrated to gradually improve the skill of 2-m temperature and sea surface temperature, although precipitation prediction remains a difficult problem. This paper reviews some of the NMME-based contributions to seasonal climate prediction research and applications, progress on scientific understanding of seasonal prediction and multimodel ensembles, and new techniques. Several prediction- oriented aspects are explored, including model representation of observed trends and the underprediction of below-average temperature. We discuss potential new directions, such as higher-resolution models, hybrid statistical- dynamical techniques, or prediction of environmental hazards such as coastal flooding and the risk of mosquito-borne diseases.