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Long-range or Seasonal forecast charts are derived from an ensemble (separate from the extended range ensemble) run on the 1st of each month out to 7 months, extended to 13 months each quarter (i.e. every 3 months).   The charts available mostly cover 3-month periods, with the first valid period typically beginning 1 month after data time.
Charts available:

• Monthly mean probability of anomaly charts - to highlight areas where ensemble forecast values depart significantly from the S-M-climate for each location within the chart area. (Example chart).
• Climagrams - box and whisker diagrams comparing the distributions of parameter averages within pre-defined regions:
  • as forecast by the seasonal ensemble,
  • as represented in the S-M-climate re-forecasts,
  • and as represented in re-analyses.
    (Example climagram).
• Tropical storm probabilities and anomalies against S-M-climate. (Example chart).
• Niño plumes - show the range of seasonal forecasts of sea-surface temperature over pre-defined regions of equatorial Pacific. (Example plume).

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Provided alongside the forecasts are measures of the skill (Relative Operating Characteristics (ROC) and reliability that were "achieved" within the respective re-forecast periods.  Forecasters should always consider forecasts at these longer lead times in the context of these verification scores.  Using verification metrics to aid assessment of the predictability.  (Example ROC diagram, example reliability diagram).

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