seasonforecasts

ECMWF SEAS5 seasonal forecast maps

ECMWF SEAS5 seasonal forecast maps for temperature, precipitation, pressure and SST. Compare SEAS5 with UK Met Office, Météo-France, DWD and CMCC on one shared valid period.

SEAS5 is the fifth generation of the ECMWF seasonal forecasting system, operational since November 2017. It couples the Integrated Forecasting System atmosphere with the NEMO ocean model and an interactive sea-ice model. Real-time forecasts start on the first day of each month with 51 ensemble members, and ECMWF also runs a multi-decade hindcast that C3S uses to define the model climate.

On this site SEAS5 appears as system 51, the version identifier in the Copernicus catalogue. Probabilities are computed from all 51 forecast members against 25 hindcast members for each of the 24 reference years.

At a glance

CentreEuropean Centre for Medium-Range Weather Forecasts
SystemSEAS5 (C3S system 51)
Forecast members used51
Hindcast members25 per hindcast year
Reference period1993–2016 hindcast climatology
Grid1° global, ±85° latitude shown
Lead timesSix monthly leads; four three-month windows
Fields2 m temperature, precipitation, mean sea-level pressure, sea-surface temperature
Forecast typesEnsemble mean anomaly, tercile summary, median exceedance, tercile and quintile probabilities
SourceCopernicus C3S seasonal forecast catalogue

New initializations are imported monthly. The system version is taken from the live Copernicus catalogue for each run, so the version shown on a map panel always matches the data behind it.

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