A Framework for Assessing Operational Model MJO Forecasts

The WCRP - WWRP/THORPEX YOTC MJO Task Force and previously the U.S. CLIVAR MJO working group has recently taken steps to adopt and promote a uniform diagnostic and set of skill metrics for analyzing and assessing operational dynamical MJO forecasts. Here we describe the framework and initial implementation of our approach using real-time forecast data from ten operational numerical weather prediction (NWP) centers. The objectives of this activity are to provide a means to (1) quantitatively compare MJO forecast skill across operational centers, (2) measure gains in forecast skill over time by a given center and the community as a whole, and (3) facilitate the development of a multi-model forecast of the MJO. The Climate Prediction Center (CPC) within the National Centers for Environmental Prediction (NCEP) is hosting the acquisition of the data, application of the MJO diagnostic and realtime display of the standardized forecasts. The activity has already contributed to the production of 1-2 week operational outlooks at NCEP and activities at other centers. Further enhancements of the diagnostic's implementation, including more extensive analysis, comparison, illustration and verification of the contributions from the participating centers will increase the usefulness and application of these forecasts and lead to more skillful predictions of the MJO and indirectly extra-tropical and other weather variability (e.g., tropical cyclones) influenced by the MJO. The purpose of this paper is to inform the larger scientific and operational forecast communities of this effort and invite participation from additional operational centers.