Time-longitude (Hovmoller) section of various OLR anomaly products averaged from 7.5S to 7.5N. For times before and up to the present (as indicated by the horizontal solid line), the shading is for the actual observed daily OLR anomalies, smoothed in time by a 1-2-1 filter, and smoothed in space by a R21 spherical spectral truncation. These are anomalies with respect to the long-term mean and annual cycle. Contoured are the anomalies calculated by filtering the OLR for the specific regions of the wavenumber-frequency domain defined in Fig. 1a or 1b. Note the close correspondence between the solid (negative) contours of the filtered fields and the blue (negative) shading of the observed anomalies. Below the horizontal solid line are the forecasts of the various modes of variability (indicated by the contours), with the sum of the forecasts of the modes being shaded. The forecasts out to 14 days are shown.