Page History

...

• Weekly mean anomaly charts - to highlight areas where mean forecast values depart significantly from the SUBS-M-climate for each location within the chart area. (Example chart).
• Weekly probability anomaly charts - to highlight the probability of being above the SUBS-M-climate mean for each location within the chart area. (Example chart).
• Weekly probability charts - to show the probability the weekly mean anomalies will be in lower and upper quantiles of the SUBS-M-climate for each location within the chart area. (Example chart).
• Weekly averages of the monthly forecast ensemble for several variables on a single chart. (Example chart).
• Tropical cyclone probability charts (including genesis) - to indicate tropical cyclone threat and intensity worldwide and compare with tropical cyclone frequency and intensity in the SUBS-M-climate. (Example chart).
• Time-longitude (Hovmoeller) diagram of the observed and forecast ensemble mean anomaly of 500hPa or 1000hPa geopotential (in dam) in the extra-tropics - to show persistence and progression of disturbances and potential interaction between upper and lower features. (Example diagram).
• Madden-Julian Oscillation (MJO) index metrics and Wheeler-Hendon MJO diagram - to show recent and forecast evolution and uncertainty of MJO features. (Example MJO index metrics Hovmoeller diagram, example Wheeler-Hendon MJO diagram).

...

Seasonal ensemble (7 to 13 months period)

Long-range or Seasonal forecast charts are derived from an ensemble (separate from the sub-seasonal 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).

Verification Metrics for

...

Sub-seasonal and Seasonal forecasts

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).

...