18/May/2025

Updated status of the changes to operational forecast systems

The availability of documentation pages and hindcast data for this forecast system will be communicated closer to the switchover date. At least on the 10th of the month prior to that release date, the initial set of hindcast (re-forecast) data will be released in the C3S seasonal forecast datasets on the Climate Data Store.

10/May/2025

(UPDATED 20/May/2025) Temporary gap in BOM graphical products has been fixed

Due to a technical issue the plots for "Probability of exceeding the median" from BOM contribution to C3S were temporarily unavailable for T850 and Z500 variables. This issue has been now fixed (20/May/2025 9UTC) and all plots are now available

16/April/2025

Updated status of the changes to operational forecast systems


The documentation for these forecast systems can be found in the corresponding Knowledge Base pages linked in the previous paragraphs. The hindcast data for these forecast systems will be progressively processed by C3S and made available via the Climate Data Store. The evolution of the available start dates from each forecast system can be monitored in the table "Hindcasts" of our "Summary of available data"

Note that during the processing and archival of the hindcast data for these systems the CDS download forms won't be updated as frequently as new data is made available. That means some dates can temporarily appear as unavailable in the CDS forms. In those cases, marked with a * close to the (tick) icon in the "Summary of available data", data will be temporarily only available via the CDS API.


The availability of documentation pages and hindcast data for this forecast system will be communicated closer to the switchover date. At least on the 10th of the month prior to that release date, the initial set of hindcast (re-forecast) data will be released in the C3S seasonal forecast datasets on the Climate Data Store.

10/February/2025

(UPDATED 7/March/2025) Planned changes to operational forecast systems

In the coming months several system upgrades are expected from the seasonal forecast providers to C3S. Additionally, we will soon see the incorporation of a new contributor to the C3S multi-system - the Australian Bureau of Meteorology (BoM).

The following dates have been now confirmed:

The documentation for these forecast systems has been now published in the corresponding Knowledge Base pages (following the links in the previous paragraph)

Please note that at least on the 10th of the month prior to those release dates, the initial set of hindcast (re-forecast) data will be released in the C3S seasonal forecast datasets on the Climate Data Store.


Decisions on CMCC SPS4 forecast system are still pending. Details will be communicated as soon as they are available.

10/December/2024

Issue affecting UK MetOffice GloSea6 seasonal forecast data for December 2024 real-time forecast

Due to a technical issue with the production of MetOffice GloSea6 data files for C3S contribution, some ocean2D monthly data files haven't been succesfully produced for start date 20241118 and realization 002. Because of that all ocean2D monthly data files for this member have not been published on the CDS seasonal-monthly-ocean dataset.

The affected ensemble member corresponds to number "27" of the December 2024 nominal start date real-time forecasts.

Please note that data from this member in all other CDS datasets haven't been affected by this issue and they are available as usual.

This has been recorded as "Data gap G11." in C3S Seasonal Forecast known issues

2/December/2024

Issue affecting C3S seasonal forecasts verification plots has been now fixed

The issue reported on 19/September/2024 affecting some of the plots displayed on our verification page (C3S seasonal forecasts verification plots) has been now addressed. Wrong plots have been corrected and all plots are now available on the page.

10/October/2024

(UPDATED 28/October/2024) Planned changes to operational forecast systems

In the coming months several system upgrades are expected from the seasonal forecast providers to C3S. Additionally, we will soon see the incorporation of a new contributor to the C3S multi-system - the Australian Bureau of Meteorology (BoM).

More details will be given in due course, as some of the dates are still tentative; this is a first announcement about the upcoming changes.

*(UPDATE NOTE)
Due to a set of technical issues, the previously announced operational changes planned for November 2024 (CMCC upgrade to SPS4 and introduction of BOM ACCESS-S2) have been now delayed. Details about new timelines will be communicated when they become available.

10/October/2024

New variable available: soil moisture

With the release of the October 2024 real-time forecast a new variable, volumetric soil moisture, has been included in the C3S seasonal forecast datasets available through the Climate Data Store (CDS). Users should be aware of the following elements:

19/September/2024

Issue affecting C3S seasonal forecasts verification plots

Some of the plots routinely displayed on our verification page (C3S seasonal forecasts verification plots) have been temporarily removed, upon finding them to have been affected by a computational error in our processing chain. The affected diagnostics are the maps of correlation for the 3-month aggregations, for all the variables. 

Once corrected versions of these diagnostics are computed, an announcement will be posted on these pages and the revised plots will be uploaded to the webpage. In the meantime users can reproduce these plots by following the workflow described in the C3S Jupyter Notebook tutorial on seasonal forecasts verification (https://ecmwf-projects.github.io/copernicus-training-c3s/sf-verification.html)

10/September/2024

The new Climate Data Store (CDS-Beta) is now live and it soon will become the operational instance of the CDS. Users are encouraged to migrate as soon as they can

https://cds.climate.copernicus.eu/

Remember that you need to have an ECMWF account to use CDS-Beta. Your existing CDS credentials will not work in CDS-Beta! If you do not yet have an ECMWF account, please create one here, then with your ECMWF login account, login to CDS-Beta and follow instructions online.
API users need to upgrade their cdsapi package and update their credentials.

You can find the most relevant and up-to-date information about this migration in the following page: https://confluence.ecmwf.int/display/CKB/Please+read%3A+CDS+and+ADS+migrating+to+new+infrastructure%3A+Common+Data+Store+%28CDS%29+Engine

Important to note:


19/July/2024

C3S graphical and data products from July 2024 forecast

The issue reported on 10 July 2024 (below), related to errors in the July-start forecast data from ECCC's new operation system, CanSIPSv3.0, has now been resolved. Corrected data has been acquired, processed and archived, and ECCC graphical and data products have been published. Data with July starts from ECCC's systems 4 and 5 (in the CDS notation) can now be downloaded from the CDS. Any data from these systems  downloaded from ECMWF's MARS archive before 19 July 2024 may be flawed; data downloaded after this date is expected to be error-free.

Unfortunately, hindcast data with August start from these new systems have not yet been made available (in line with the usual practice of publishing hindcasts at least one month before the corresponding real-time forecasts). This data will be processed and published, at the latest at the same time as the August 2024 forecast. The advance publication of hindcast data will be resumed as soon as possible.

17/July/2024

C3S graphical and data products from July 2024 forecast

The corrected DWD July-initialised real-time forecast has now been published, both in the set of graphical products on the website (https://climate.copernicus.eu/charts/packages/c3s_seasonal/) and in the respective datasets of the CDS. Data downloaded from the CDS after 16 July 2024 13 UTC  is expected to be error-free. The original error only affected one member of the real-time DWD forecast ensemble; however, all ensemble members have now be re-archived. 

10/July/2024

C3S graphical and data products from July 2024 forecast

Due to potential data quality issues, the suite of graphical seasonal forecast products with July 2024 initial conditions (available at https://climate.copernicus.eu/charts/packages/c3s_seasonal/) do not include the contribution from DWD, at the time of publication. (They also do not include ECCC forecasts - see announcement below.) The DWD July real-time forecast data has been processed and archived, and it is downloadable from the CDS forms and API, but we do not endorse its use until further investigation is completed. Initial examination points to the 22nd member of the ensemble (in the order archived) having been started from wrong initial conditions; at present, there is no guarantee that the other members are 'correct'.

10/July/2024

Update on changes to ECCC operational forecasting systems:

Due to issues with the acquisition of data from the new Environment and Climate Change Canada (ECCC) seasonal forecasting systems, the ECCC July 2024 forecast will not be available, at the usual publication time, as data or graphical products. Neither forecast nor hindcast data are available via the CDS forms of the CDS API; however hindcast and real-time forecast data have been archived in MARS, but should not be used until further notice, pending tests to ensure data quality and consistency. ECCC is not part of the multi-system combination this month. 

Products from ECCC's July 2024 forecast may be created and published by C3S at a later date, but the real-time multi-system combination will not be updated.

 A reminder that the previous ECCC systems (CanCM4i and GEM5-NEMO) have been discontinued.

28/June/2024

Planned changes to operational forecasting systems:

Environment and Climate Change Canada (ECCC) will update its seasonal forecasting systems to new versions from July 2024. The new Canadian Seasonal to Interannual Prediction System version 3.0 (CanSIPSv3.0) is a multi-model ensemble composed of two individual forecast systems CanESM5 and GEM5.2-NEMO. ECCC's operational forecast system is one of the components of the C3S seasonal forecast multi-system. 

22/March/2024

An issue potentially affecting C3S seasonal forecast data downloads from the CDS has been recently detected.

The source of the issue has been identified and the problem reverted, so CDS is now back to its correct behaviour. However, we strongly advise users which have requested data that matches the description below to repeat those downloads to ensure the data retrieved is correct.

The affected data downloads would have been those requesting data in netCDF format from one of the following seasonal forecast datasets (where the data is stored in GRIB) between Tuesday 19th of March and Thursday 21st of March (both included):

CDS data requests matching that description have very likely received wrong data inside the netCDF files.

More details can be found in the complete issue description on the C3S User Forum: https://forum.ecmwf.int/t/check-your-recent-netcdf-files-downloaded-from-the-cds-and-ads-you-may-need-to-download-them-again/2280

11/December/2023

With the release of December 2023 forecasts (10th December 2023) a new view of the SST indices time series have been included for the ENSO regions in the C3S seasonal graphical products (https://climate.copernicus.eu/charts/packages/c3s_seasonal)

In addition to the plot showing individual ensemble members a new time series plot is now available showing some of the percentiles for each month's distribution. This was already available for the IOD indices and it has been now also extended to ENSO indices.

image-2023-12-11_14-4-29.png

22/November/2023

Please note that a "data gap" issue has been documented in our C3S Seasonal Forecast known issues page affecting availability of MetOffice system 602 hindcast data for December nominal start dates (see details for issue G10. in the "Data gaps" table)

10/November/2023

Please note that a "data gap" issue has been documented in our C3S Seasonal Forecast known issues page affecting availability of MetOffice system 602 hindcast data for November nominal start dates (see details for issue G10. in the "Data gaps" table)

8/September/2023

Please note that a "data gap" issue has been documented in our C3S Seasonal Forecast known issues page affecting availability of MetOffice system 602 data for 8/August/2023 (see details for issue G10. in the "Data gaps" table)

9/August/2023

Please note that a "data gap" issue has been documented in our C3S Seasonal Forecast known issues page affecting availability of MetOffice system 602 data for 15/July/2023 (see details for issue G9. in the "Data gaps" table)

20/July/2023

New C3S seasonal forecast products available: 10m wind speed and sea ice concentration plots; additional documentation and training materials

Soon after the release of our July 2023 seasonal forecasts new features have been made available to users of the C3S seasonal forecast service:

9/June/2023

New C3S seasonal forecast products available: total column water quantities data and SST indices verification plots

With the release of our June 2023 seasonal forecasts a couple of additions have been made to the offering of the C3S seasonal forecast service:


Please also note that a "data gap" issue has been documented in our C3S Seasonal Forecast known issues page affecting availability of NCEP CFS2 data for 22/May/2023 (see details for issue G8. in the "Data gaps" table)

10/March/2023

New C3S seasonal forecast dataset and earlier publication date

With the release of our March 2023 seasonal forecasts a new dataset has been included, containing global ocean monthly data for a set of variables in the upper part of the ocean. 

More details here: Seasonal forecast monthly averages of ocean variables

Additionally, we would like to remind our users that starting today, 10th March 2023, all the products from the C3S seasonal forecast component are made publicly available on a slightly earlier schedules:

1/March/2023

Summary of new features in C3S seasonal forecast service

Around the release of our March forecast a few new features enhancing the service are being put in place, from changes in the publication date of the data and products, to the inclusion of new features in the web application displaying our graphical products, and including information about verification of the forecast systems. A new seasonal forecast dataset will be published in the CDS catalogue, as described below.


13/Jan/2023

Introduction of new features in plots and data

With the release of January 2023 C3S seasonal forecast the following changes have been introduced:


14/November/2022

Completion of ECMWF Data Handling System (DHS) move.

At 18:41 on Friday 11/November/2022 the disruption to the ECMWF DHS, where C3S seasonal forecast data is hosted, was declared as finished marking the successful completion of the move from Reading headquarters to Bologna Data Centre.

30/October/2022

Data availability during ECMWF DHS move
(Announcement date: 31/August/2022. Update: 30/October/2022)

(Announcement date: 31/August/2022. Update: 12/October/2022)

The data listed in the following table is expected to be available during the limited access period (5-6 weeks from 8/Sep/2022) caused by ECMWF move of its Data Handling System to Bologna.

Users are encouraged to download before 8/Sep/2022 any data not listed in the table they might need during that period. Any change to this schedule will be announced here.

Data streamsForecasting systems(1)Nominal start dates
daily dataMetOffice GloSea6 (system=601)Sep to Dec 1993-2016
All operational systemsSep and Oct 2022 (2)
monthly dataAll operational systemsJun to Dec 1993-2016
All operational systemsMar to Oct 2022 (2)
ECMWF SEAS5 (system=51)Oct to Dec 1993-2016
anomalies data (3)All operational systemsMar to Oct 2022 (2)

NOTES:
(1) This is the list of all currently operational forecasting systems: ECMWF SEAS5, Météo-France System8, MetOffice GloSea6 (system=601), CMCC SPSv3.5, DWD GCFS2.1, NCEP CFSv2, JMA CPS3, ECCC CanCM4i and ECCC GEM5-NEMO

(2) Real-time forecast data won't be available until its usual release date (13th of the month at 12 UTC)

(3) This also includes the data used to compute the anomalies ("ensemble mean" and "hindcast climate mean") which are available via the "monthly" CDS datasets


12/October/2022

Changes to operational forecast system from ECMWF

From November 2022 a new version of ECMWF SEAS5 output will substitute the current one. This new version (v5.1) will be labelled with the keyword system=51  

  • What are the changes in this new version of ECMWF SEAS5 data?
    • A different interpolation tool has been used to produce the 1-degree grid, both for hindcasts and real-time forecasts.
    • A new 1-degree grid, now consistent with the grid available from the other participating forecast systems. Specifically, it will have grid-points centered at half-degree latitude/longitude, and hence it has 180 values in the latitude coordinate (from -89.5 to 89.5) instead of the current 181 values (from -90 to 90)
    • A couple of additions to complete the list of available variables: Top solar incoming radiation and 1000hPa level for the 5 variables available at pressure levels. Additionally, on top of the values of runoff, for SEAS5.1 both sub-surface and surface runoff will be also available.


  • What are the implications for users of ECMWF SEAS5 data? 
    • (warning) From November 2022, only system=51 real-time forecast data will be available from the CDS
    • (warning) Users will need to use system=51 hindcast data alongside the new real-time forecasts.
      Data from the current version (system=5 ) should not be used, so those users with previously downloaded hindcast data will need to download the new version.
    • At the time of this announcement, hindcast data for October, November and December has been made available on the CDS
      • The remaining start dates (from January to September) will be processed and published progressively following the calendar order. Details on their availability can be found in the "Hindcasts" table of the Summary of available data
      • Please note that while the ECMWF DHS move hasn't been completed, not all data will be available from the CDS (details in the table above with "DATA AVAILABILITY DURING ECMWF DHS MOVE")


  • Why have these changes been introduced?
    • When ECMWF SEAS5 was released in 2017, the C3S 1-degree version was created with the default interpolation tool (emoslib ) available from MARS. With the migration of ECMWF computing infrastructure to its new Data Centre in Bologna, this tool has been discontinued. That means new real-time forecasts produced after the migration can't be produced anymore in a way consistent with the available SEAS5 hindcast in the CDS. After careful evaluation of the impact of the interpolation, it was decided to create a new version of the hindcast data. This has been labelled as SEAS5.1 and encoded with keyword system=51.
    • With this new version of SEAS5 hindcast, a couple of additional improvements were also included:
      • A new 1-degree grid consistent with the one provided for other forecast systems (see details above)
      • A couple of additions to the list of variables (see details above).

12/October/2022

Changes to stratospheric (10hPa) zonal wind plots from the October 2022 real-time forecast release

A couple of bugs have been fixed which affected the plots shown here: https://climate.copernicus.eu/charts/c3s_seasonal/

12/July/2022

An error has been identified in "sea surface temperature" and "land surface temperature" (called 'soil temperature level 1' in the CDS) data from CMCC SPSv3.5 forecasting system. The details can be found in the section "Not fixed errors" under the code E10 of our "Known issues" page

It affects the following data for those two variables:

According to CMCC report about the issue:

The problem only affects the points at the borders between the three realms (sea ice, ocean and land), and is due to a change in the land-sea or sea ice-sea mask interpolation algorithm, which was implemented in the forecasts (starting from March).
Therefore, the anomalies of the above mentioned variables show unrealistic patterns near the sea-land or sea-sea ice boundaries, because, in these grid points, the new interpolation algorithm has made the forecasts, from March onwards, inconsistent with the hindcasts.
Starting from the August 2022 real-time forecast, it will be restored the procedure used in the hindcasts.

9/May/2022

Reminder of impacts of ECMWF's Data Handling System (DHS) move to Bologna

As work to move ECMWF's DHS to Bologna progresses, the dates when users of C3S seasonal forecast data might experience disruptions are approaching.

11/ February/2022

3/January/2022

Changes to operational forecasting systems from Japan Meteorological Agency (JMA)

8/December/2021

Changes to operational forecasting systems from Environment and Climate Change Canada (ECCC)

15/November/2021

Planned changes to operational forecasting systems:

12/October/2021

An issue with sporadic anomalous values in "2m dewpoint temperature" from Météo-France System8 has been identified. The details can be found in the section "Fixed errors" under the code E9 of our "Known issues" page

29/September/2021

An error has been identified in the "total cloud cover" data from JMA CPS2 forecasting system. The details can be found in the section "Not fixed errors" under the code E8 of our "Known issues" page

It affects all available data for that variable (daily data, monthly data and anomalies) both for real-time forecasts and hindcast dates.

Due to a bug during the data ingestion to the C3S archive the values of this parameter have been divided by 100.

6/July/2021

Changes to operational forecasting systems:

23/May/2021

Changes to operational forecasting systems:

13/May/2021

Changes to operational forecasting systems:


11/Mar/2021

A data gap in MetOffice's GloSea6 forecast data has been reported as "Data gap G5" in C3S Seasonal Forecast known issues

The GloSea6 forecasts initialised on 22 and 23 February were initialised with low Arctic sea ice extents. This resulted from corrupt data used in the derivation of ocean initial conditions. The sea ice largely recovers in these forecasts, but is biased low through the whole 6-month forecast compared to neighbouring days.

Initial sea-ice conditions for different GloSea6 February 2021 start dates:

Evolution of sea-ice fraction forecasts for different GloSea6 February 2021 start dates:


2/Mar/2021

The integration into C3S seasonal forecast multi-system of ECCC forecasting systems, CanCM4i and GEM-NEMO, announced earlier (19th/January/2021) to happen with the release of March 2021 real-time forecasts has been delayed to April 2021.


16/Feb/2021

Changes to operational forecasting systems:


19/Jan/2021

Upcoming changes in the C3S seasonal forecast service planned to be implemented for the release of the March 2021 real-time forecast (13th March at 12GMT):

More details about these planned changes will be soon notified. Please note this is just an early warning about the plans for implementation of those contributions and changes to that schedule are still possible.

14/Dec/2020

With the publication of the December 2020 C3S seasonal forecasts (released on the 13th December at 12UTC) a couple of new additions have been made to the catalogue of graphical products shown at https://climate.copernicus.eu/charts/c3s_seasonal/:


26/Oct/2020

An issue in the CDS infrastructure affecting some seasonal forecast retrievals has been identified. It will be tracked as error (E7b) in the seasonal forecast known issues page.

This error prevents users from getting all available members from CFSv2-v20110310 (NCEP CFSv2) data. This issue affects retrievals done after the release of the October 2020 forecast, which happened at 12UTC on the 13th of October 2020.

It affects all data available in the high-frequency (daily/subdaily) datasets:

Members with start time at 06h,12h and 18h are not being retrieved from the archive by the CDS and just members with start time at 00h are returned.

This is currently under investigation and it will be announced here once the issue has been resolved.

The issue described above has been solved at 16:15UTC on the 26/October/2020. All retrievals should be correct now, and just those retrievals performed between 13/Oct/2020 at 12UTC and 26/Oct/2020 at 16:15UTC have been affected.


13/Oct/2020

With the release of the October 2020 real-time forecast (at 12 UTC on 13th October) some additions will be introduced to the list of available forecasting systems. Specifically:

Additionally, with the release of the November 2020 real-time forecast (at 12 UTC on 13th November), another change of forecasting systems will be included. Specifically:

Details about hindcast dates available can be found here. The complete list of parameters available for each forecasting system can be found here.

13/June/2020

All these changes have been introduced starting from June 2020, and previously produced plots haven't been affected by them.


15/May/2020

12/ May/2020

25/March/2020

11/February/2020

8/January/2020

13/December/2019

2/December/2019

29/November/2019

7/November/2019

11/October/2019

22/August/2019

5/April/2019



This document has been produced in the context of the Copernicus Climate Change Service (C3S).

The activities leading to these results have been contracted by the European Centre for Medium-Range Weather Forecasts, operator of C3S on behalf of the European Union (Delegation agreement signed on 11/11/2014). All information in this document is provided "as is" and no guarantee or warranty is given that the information is fit for any particular purpose.

The users thereof use the information at their sole risk and liability. For the avoidance of all doubt, the European Commission and the European Centre for Medium-Range Weather Forecasts have no liability in respect of this document, which is merely representing the author's view.