Integrated Forecast System

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IFS Ensemble and Deterministic outputs

The Integrated Forecast System (IFS) is an operational global meteorological forecasting model. IFS is developed and maintained by the European Centre for Medium-Range Weather Forecasts (ECMWF) based in Reading, England. Because of its source, it is often known as the "ECMWF" or the "European model" in North America, to distinguish it from the American Global Forecast System (GFS). Along with the NWS's Global Forecast System, which runs out to 16 days, the CMC's Global Environmental Multiscale Model (GEM), which runs out 10 days, the Naval Research Laboratory Navy Global Environmental Model (NAVGEM), which runs out eight days, and the UK Met Office's Unified Model, which runs out to 6 days, it is one of the five predominant synoptic-scale medium-range models in general use.

The IFS is a global model that runs every twelve hours. Its output runs out to fifteen days in one-day intervals (although output is only made available to most members of the public out to 7 to 10 days, depending on the variable). The operational model runs both in a deterministic forecast mode and as a 51-member ensemble. The current deterministic mode has a horizontal resolution of 16 km while the ensemble prediction systems have resolutions of 32 and 64 km, and 137 layers in the vertical resolution in the deterministic compared to 91 layers in the ensemble; both modes' vertical layers follow terrain at low levels. The IFS, like the GFS, uses spectral representation rather than a grid-based system.

Information from the IFS is proprietary and copyrighted, though the ECMWF has made a limited amount of the model's most important calculations available to the public; this public data is, by declaration of the ECMWF, in the public domain.[1] In the United States, the IFS is generally used as a comparison against the American GFS model in the forecast period between four and ten days.


  1. ^ "New web products from the ECMWF ensemble prediction system". ECMWF. 2010-05-14. Retrieved 2012-01-13. 

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