Sub-seasonal to Seasonal Predictability in the NMME

The North American Multi-Model Ensemble (NMME) experiment is an unprecedented effort to improve intraseasonal to interannual (ISI) operational predictions based on the leading North American climate models. As of May 2016, the NMME seasonal prediction system has completed transition to NWS operations. The objectives of the NMME project include: (i) Continued real-time forecasts and incorporating updated models; (ii) coordinated predictability research that identifies the benefit of the multi-model approach; (iii) developing and evaluating an intraseasonal protocol; and (iv) continued and enhanced data distribution to facilitate use of NMME data. This talk highlights the evolution of the project in terms of its goals, the retrospective forecast skill with particular emphasis on droughts and floods throughout the continental US. This talk also discusses forecast skill and predictability (both homogeneous and heterogeneous) during the real-time phase (i.e., 2010-present) and how this compares with the historical forecast period. Essentially, we seek to address the question of whether the skill and predictability estimates based on retrospective forecasts agree with our real-time experience. All of the above analysis and assessment is performed in a multi-model context so the results are relatively robust with respect to differences in model formulation.