Implemented by the European Commission as part of the Copernicus Programme

Seasonal and sub-seasonal outlook (GloFAS Seasonal)

GloFAS Seasonal is the first operational global scale seasonal hydro-meteorological forecasting system, launched in November 2017. From GloFAS 3.1, GloFAS Seasonal couples seasonal meteorological forecasts from ECMWF with the LISFLOOD hydrological model to provide openly available weekly probabilistic forecasts of river flow out to 4 months for the global river network.

How are GloFAS Seasonal forecasts generated?

From GloFAS 3.1, GloFAS Seasonal modelling chain is based on the LISFLOOD hydrological model forced by an ensemble of meteorological forcings. A 5-day monitoring analysis of the latest observations based on the latest ECMWF reanalysis when available is used to initialize the forecasts, followed by seasonal ensemble forecasts for 16 weeks from the latest ECMWF Seasonal Forecast System, SEAS5. The resulting 16 weeks simulated daily hydrological forecasts are then averaged by calendar weeks (GloFAS Seasonal) and compared with GloFAS Seasonal reforecasts to create an ensemble of weekly river flow anomalies, converted into a probability of unusually high of low flows.

Which products does GloFAS Seasonal offer?

GloFAS Seasonal offers a range of forecast products and associated information, accessible via different layer tab of the GloFAS map viewer:

GloFAS Seasonal products are updated monthly and published on the 10th of each the month. Detailed information on GloFAS Seasonal products can be found on the GloFAS wiki pages.

GloFAS Seasonal reference discharge runs

GloFAS Seasonal reference discharge runs are a collection of discharge simulations as close as possible to GloFAS Seasonal operational system.
GloFAS Seasonal reforecasts are forecast simulations performed for a set of past dates using the latest ECMWF Seasonal forecasting system, based on a configuration as close as possible to GloFAS Seasonal operational setting, initialised using GloFAS reference long run. They are used to compute GloFAS Seasonal reference discharge runs and to analyse GloFAS Seasonal forecast performance systematically over a long period.
GloFAS Seasonal discharge thresholds are a set of maps of weekly-averaged discharge magnitude corresponding to the 20th and 80th percentile values (respectively called low and high flow thresholds). There is a set of maps for each week of the year and each lead time from 1 week to 16 weeks. The percentiles are derived from GloFAS Seasonal forecast reruns for the corresponding week of the year and lead-time sample. GloFAS Seasonal discharge thresholds are used to generate river flow anomaly forecast maps.

GloFAS Seasonal data

GloFAS Seasonal data is a gridded dataset at 0.1° horizontal resolution. It contains:

For more details on the latest GloFAS configuration, please refer to the GloFAS wiki pages.