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Please see the respective links for guidance and workarounds.

Amended data errors

  1. Wrong values of wind speed monthly means for MetOffice data [FIXED]
  2. Wrong values of snowfall amount for CMCC data [NOT FIXED]

  3. Wrong data of pressure level variables for DWD data [FIXED]

Data and metadata deficiencies

Known issue numberCentreForecasts
Start dates(1)Description

Met Office
(all systems)


Near-surface temperatures (6-hourly and daily minimum and maximum) and dewpoint temperature are encoded as being calculated at a height of 2m.
Those parameters are calculated at 1.5 meters height in Met Office seasonal forecast systems


Met Office


Hindcasts: May-Dec and January
Forecasts: Sep2017 to Jan2018

Global grid is incomplete (just 180 latitude points, between 90S and 89N)
Requests with MARS-based interpolations (i.e. using "grid=NN/NN") won't work unless a suitable regional subselection is requested (with "area=LL/LL/LL/LL")

Note that additionally, in this grid all points are set at integer values of latitude/longitude


All parameters on pressure levels are not globally complete, having "missing value indicators" in points below the orography.


There is an issue with the postprocessing used at origin of the lagged start dates.

Only members #27 to #51 are affected having data with a time shift of 7 days (168 hours). For instance, data with date/time labelled as YYYYMM08 00h would in fact correspond to YYYYMM01 00h.

HindcastsYears between 1993 and 1999

There are anomalous values of SST (and associated parameters, e.g. fluxes, and vertical oceanic temperature profiles) appearing in the first hours of a very limited number of ensemble members of forecasts.

The issue is caused by a bug in the oceanic perturbation generation tools used at origin to produce the ocean initial conditions.  The errors/perturbations appear initially as excessively high SST values, confined to the reported hindcast years, in a limited number of grid points all in the tropical Pacific. They are very quickly dissipated by the coupled model physics and dynamics, affecting, therefore, only the first 24 hours of the forecasts at most.


There are some variables affected by a spin-up issue. This affects just some ensemble members depending on the initial conditions each member started from. Unfortunately, as the selection of the forecast members is done randomly from a bigger pool of initial conditions, there is no metadata describing this in the current service based on GRIB files stored in ECMWF's MARS archive.



HindcastsAll 2017 start datesFor this forecasting system, year 2017 start dates have been computed as hindcasts and not real-time forecasts.
BothAllFor this forecasting system, the evaporation field is masked over the ocean (only land points are available)
D9.Met Office
BothAllThe fractional land-sea mask doesn´t match the masked (land-only or sea-only) fields. For the files affected, the land-sea mask provided was produced as the result of a 1-degree interpolation of the binary land-sea mask in the native model resolution

Data gaps

Known issue numberCentreForecasts
Start dates(1)Description

Met Office



No data is available

Met Office

ForecastsNominal start dates previous to November 2018Monthly statistics and anomalies are just available for 50 members - specifically, the 50 members closest and previous or equal to the 1st of the nominal start month.


(1) See description of nominal start dates here