The introduction of the Release Candidate Phase (RCP) for IFS Cycle 50r1 is planned for January 2026.
From January 2026, Cycle 50r1 forecast production will run in parallel with the operational system, giving users time to test the new output and prepare their workflows.
Cycle 50r1 includes major scientific and technical updates across the model, data assimilation, coupling, and forecast systems. These enhancements cover the ocean, sea ice, wave and atmospheric components, along with several technical configuration changes. There are no changes to horizontal, vertical or temporal resolution in this cycle.
Following the alignment of the high-resolution forecast (HRES) and the ENS control in Cycle 49r1, Cycle 50r1 will introduce a structural adjustment: the current ENS control will no longer be produced, and the data stream previously known as HRES will become the new ENS control.
More information on the upgrade can be found here: Implementation of IFS Cycle 50r1 - Forecast User - ECMWF Confluence Wiki
Users with an ECMWF Service Agreement are strongly encouraged to register their host configuration details to receive test products via dissemination: RCP 50r1 - Test System User Details - Data and Charts - ECMWF Confluence Wiki. Your early completion of this form will expedite the process in January 2026. Note, however, that changes to hosts and destinations will be paused for the festive period (see here).
For any questions, please reach out to us via the ECMWF Support Portal.
ECMWF Support