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Registered EFAS users with access to EFAS real-time information can access real-time EFAS hydrological forecasts through the ECMWF Production Data Store (ECPDS). The data (hydrological time series for each ensemble member for the entire EFAS domain) is stored as one grib file per forecast with the naming convention of efas_foreacstdate.grb / efas_YYYYMMDDTT.grb, for example, "efas_2019040300.grb" for forecast produced the 3rd of April 2019 using 00UTC meteorological forecast forcing. All forecast time steps (i.e. from day one to day 10) are within the same file for easier access. The data is kept on the server for 30 days from the day it was produced. For later dates, please refer to the CDS.

The data is restricted to authorised EFAS users and is password protected. User ID is the first part of your email before the '@' address; your password will be provided by email after registration to the service. To subscribe, please log a request using the ECMWF Support Portal. (Documentation on how to log a request is here).

titleECPDS User Documentation

Before accessing the data, it is recommended that you read the related documentation:  ECMWF Production Data Store (ECPDS)

User guide

Browsing the data

From 12 UTC Tuesday 18th October 2022, the data will no longer be available from ''.  Instead, please use            

After logging in, available data is shown as a list of files in the browser. The data is split into the file with all the forecasts in one file ("EFAS_forecasts_YYYYMMDDHH.grb") and the simulation forced with observations in a separate file ("EFAS_sfo, including simulations forced with observations ("SFO" grip key), in one file ("efas_YYYYMMDDHH.grb").

Automatic download is done by clicking on a file name. As each file is large, due to the amount of archived information they containit contains, downloads can be slow. Once downloaded, access to the data can be made directly from the GRIB file, or after conversion to netCDF. The recommended way to manipulate the data in either format is using python library xarray (with cfgrib extension for support to grib files).

Automatic data transfer

In addition to manual download, an automatic data transfer is also possible, where data is sent to the service subscriber as soon as it is available. If you are interested in such a service, please log a request using the ECMWF Support Portal.


Access to either real-time river flow forecasts or reforecasts from GloFAS (both GloFAS 30-days and GloFAS Seasonal) is possible through a dedicated ftp service set-up by the GloFAS team upon request. Data is provided either as point time series or 2D grid series, both in netCDF format.

A request for real-time forecasts, reforecasts, or any other inquiry and feedback on the service can be made by logging a request using the ECMWF Support Portal. The team endeavours to respond to all requests as soon as possible within 15 working days. Please provide the following information when sending a request for data, including the period of simulation requested (real-time or reforecasts):

  • Requesting data for stations/points (only for river sections with upstream area larger than 1000 km2):
    • Station ID(s)
    • Name of station(s)
    • Name of river(s)
    • Name of country
    • Station latitude(s)/longitude(s)
    • Station upstream area(s) from provider (if available)
  • Requesting data for areas:
    • Latitudes/longitudes of the bounding box region

Availability of Real-time Forecast Data

In general, the CDS should be used for user requests where you require a subset of data or certain timesteps as it offers customisable retrievals of data.

The FTP folder contains the forecasted discharge of the GloFAS operational system:


Members are numbered 00 to 50, with member 00 representing the Control Forecast member.

There is also a combined file named :


Availability of Initial Conditions

Discharge initial conditions used for every issued forecast are available in a directory named “wb_netcdf”. To find the exact one for a particular forecast base date, YMD, the file structure will be, depending on the type of meteorological forcing:

If the discharge was obtained from a simulation using ECMWF reanalysis as meteorological forcing, known as “water balance”:


If the discharge was obtained from a simulation using ECMWF NWP deterministic model forecast as meteorological forcing, known as “fillup forecast”:


Availability of Test and Legacy Data

Prior to a new release of GloFAS Forecast, we will provide a means for users to test their workflows by providing a duplicated data stream available on the FTP Service.

This data stream will mirror the existing data stream and will be stored on the FTP under the version number of the GloFAS release.

All files will use an identical folder structure to the previous release.


for_ABC ← Production Data

X.Y/for_ABC ← Test Data

As part of the release of a new forecast, we may continue to run the previous forecast cycle as a legacy suite. This suite would no longer be considered operational and would likely be discontinued after a few months.

Data will be stored in a similar way to the new test data, using the version of the previous release.


for_ABC ← Production Data

3.1/for_ABC ← Legacy Data

3.1/fc_netcdf ← Legacy Data