Empirical Extended-Range Prediction of the Madden–Julian Oscillation

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Abstract
An empirical model that predicts the evolution of the Madden–Julian oscillation (MJO) in outgoing longwave radiation (OLR) and 200-mb streamfunction is developed. The model is based on the assumption that the MJO can be well represented by a pair of empirical orthogonal functions (EOFs) of OLR and three EOFs of streamfunction. With an eye toward using this model in real time, these EOFs are determined with data only subjected to filtering that can be applied in near–real time. Stepwise lag regression is used to develop the model on 11 winters of dependent data. The predictands are the leading two principal components (PCs) of OLR and the leading three PCs of streamfunction. The model is validated with five winters of independent data and is also compared to dynamic extended range forecasts (DERFs) made with the National Centers for Environmental Prediction’s Medium Range Forecast (MRF) model. Skillful forecasts of the MJO in OLR and streamfunction with the empirical model are achieved out to abou... Abstract An empirical model that predicts the evolution of the Madden–Julian oscillation (MJO) in outgoing longwave radiation (OLR) and 200-mb streamfunction is developed. The model is based on the assumption that the MJO can be well represented by a pair of empirical orthogonal functions (EOFs) of OLR and three EOFs of streamfunction. With an eye toward using this model in real time, these EOFs are determined with data only subjected to filtering that can be applied in near–real time. Stepwise lag regression is used to develop the model on 11 winters of dependent data. The predictands are the leading two principal components (PCs) of OLR and the leading three PCs of streamfunction. The model is validated with five winters of independent data and is also compared to dynamic extended range forecasts (DERFs) made with the National Centers for Environmental Prediction’s Medium Range Forecast (MRF) model. Skillful forecasts of the MJO in OLR and streamfunction with the empirical model are achieved out to abou...