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Form of Output

ECMWF provides data from several different IFS models, each available according to when the IFS models are run, and each with different temporal resolutions in the output data.

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• most commonly as absolute values:  
  • instantaneous values,
  • averages over a period,
  • totals over a period,  
  • maxima or minima over a period.
• sometimes as:
  • anomalies relative to re-forecast data
  • an assessment of how extreme the anomalies might be (Extreme Forecast Index and Shift of Tails).

Medium range forecasts

Twice daily runs based on data times 00UTC and 12UTC are given in the ECMWF dissemination schedules:

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Note: Precipitation forecasts are provided as values accumulated from the start of the forecast integration.  The range of the daily variation of the forecast 2m temperature and wind gust is best estimated by retrieving the forecast maximum and minimum values.  The combination of accumulated and instantaneous forecast information can occasionally lead to inconsistencies as in both cases the valid time is defined as the time at the end of the period (e.g. during the passage of a cold front when significant precipitation amounts might be accumulated by the IFS models over the whole time interval though instantaneous cloud-free conditions will be shown at the end of the interval).

Extended Range forecasts

Once daily runs based on data times 00UTC are given in the ECMWF dissemination schedules:

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Note: Precipitation forecasts are provided as values accumulated from the start of the forecast integration.  The range of the daily variation of the forecast 2m temperature and wind gust is best estimated by retrieving the forecast maximum and minimum values.  The combination of accumulated and instantaneous forecast information can occasionally lead to inconsistencies as in both cases the valid time is defined as the time at the end of the period (e.g. during the passage of a cold front when significant precipitation amounts might be accumulated by the IFS models over the whole time interval though instantaneous cloud-free conditions will be shown at the end of the interval).

Seasonal forecasts

Once monthly runs based on 00UTC data time on 1st of each month run on the 5th of each month in the form:

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