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• • is run once monthly, base time 00UTC on 1st of each month and run on the 5th of each month covering the forecast period  Month 0 to month 7 month forecast (extended to month 13 every quarter).
  • has horizontal resolution of 36 Km and vertical resolution of 91 model levels.
  • has land-atmosphere and ocean-atmosphere coupling.
  • has 50 ensemble members plus an unperturbed control member.
  • the dissemination schedule is given in Section 3.1 Product Schedules:
    • Long range (Seasonal) schedules and products.  
    • The products are available on the 8th of each month.

The long-range forecast is a land and sea coupled.  It is based on an older version of the IFS and that therefore uses slightly different model physics.  It runs at 36km resolution, similar to the sub-seasonal range ENS but lower than the resolution typical of shorter range forecasts.  The chart products generally are presented in terms of anomalies relative to the seasonal model climate (S-M-climate) and are mainly shown as 3 month mean anomalies and probability of greater or lesser deviations.   From these one can infer whether conditions (e.g. temperature, rainfall, etc.) are likely to deviate from the average for the location and time of year, and whether such an anomaly could be extreme.

An important aspect of long-range forecasts is the identification of broad scale indicators or indices that represent important aspects of the global weather patterns (e.g. El Nino Niño Southern Oscillation (ENSO) index). 

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Guidance on the Interpretation of the seasonal products is discussed elsewhere in the guidein Section 8.3 Long Range Output.

Additional Sources of Information

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