We are pleased to announce that ECMWF will soon extend the dissemination of the Seasonal Forecast system (SEAS5) to include 13 months of forecast data once per quarter (February, May, August and November). The first delivery is scheduled for February 2026.
Users who do not have access to Product Requirements Editor (PREd) need to open a ticket through ECMWF Support Portal and request this change. Changes in volume may require an amendment to your Service Agreement if exceeding the current contractual volume limit.
This enhancement will be added to the Product Requirements Catalogue and as PREd snippets shortly, and further details will follow in a future update.
Please note that the extension data (months 8-13) will only be provided in the new ECMWF or WMO file-naming convention templates: File naming convention and format for real-time data
ECMWF Support