Dear user,

Welcome to the May edition (Nr. 4) of the Data Support News!

As always, we're pleased to share recent developments to help you stay ahead of key changes. A copy of this update is also available on our Data & Charts blog.

Open Data Transition - New Documentation Now Available

The move to Open Data from 1 October 2025 is progressing steadily. We have published supporting documentation to help users prepare for the transition.

Key reminders:

• The Information Cost will be removed from 1 October 2025. However, Service and Volume charges will still apply for data delivered directly from ECMWF.

• The current licence agreement remains valid until the transition date.

• Free data for research will continue to be bound by the stated Scope of Use; commercial use and redistribution will remain prohibited.

We encourage you to review the new documentation, and please don't hesitate to contact us if you have questions.

50r1 Preparation - Early Changes to IFS-Control Forecast (IFS-CF)

As you may already know, the IFS 'HRES' will be deprecated with Cycle 50r1 later in Q4 2025 with the ensemble model (IFS-ENS) taking the lead. To prepare for this, please review the following information:

• In practice, the current configuration for HRES will become the IFS-CF. This means anyone receiving stream=enfo, type=cf will need to migrate to stream=oper, type=fc (and to stream=scda, type=fc for 06z/18z runs) before the date of the implementation.
• This is something all users can do now, even before the cycle upgrade later in the year.
• Early adoption will ensure a smoother transition when the cycle implementation takes place.
• The current HRES (stream=oper, type=fc) is now bit-identical to the control forecast of the IFS-ENS (stream=enfo, type=cf). 
• At the moment, the timing will remain as per the current dissemination schedule, meaning the control will be delivered ahead of the perturbed forecasts.

For further updates, you are welcome to subscribe to our mailing list by sending an email to forecast_changes-request@lists.ecmwf.int with subscribe or unsubscribe as the subject line.

More information about 50r1 and related timelines will be shared in upcoming updates.

AIFS-Ensemble - Coming Soon

Following the operational release of AIFS-Single v1.0 in February, we're excited to announce that AIFS-Ensemble is in preparation!

• Indicative timelines for test data and the official implementation date will be communicated soon.

• There will also be a webinar introducing AIFS-Ensemble and its key features, with details to be shared in due course.

For further updates, you are welcome to subscribe to our mailing list by sending an email to forecast_changes-request@lists.ecmwf.int with subscribe or unsubscribe as the subject line.

More information about AIFS-Ensemble and related timelines will be shared in upcoming updates.

As always, we're here to support your data operations and provide clarity around changes that may affect your setup. Should you have any questions, don't hesitate to reach out via the ECMWF Support Portal.

Best regards,

ECMWF Data Support Team