New ECMWF Forecast User Guide launched

Bob Owens, Tim Hewson


A new and extensively updated edition of ECMWF’s user guide was made available online in May this year. The ECMWF Forecast User Guide helps forecasters and other meteorologists to make the best use of the Centre’s forecast products. It provides all the tools needed for the correct interpretation of these products, enabling users to deliver a high-quality service to their own customers. It also encourages users to employ new or previously overlooked forecast techniques.

The guide focuses on the medium range but also covers the increasingly important monthly and seasonal output. The correct use of probabilistic information and of departures from worldwide model climatologies is stressed throughout. While the emphasis is on ECMWF’s own web-based products, including ecCharts output, the content is also relevant to users who reference gridded data imported onto their own dedicated forecaster workstations.

The guide explains how ECMWF’s Integrated Forecasting System (IFS) works, what recent changes there have been and what these mean for forecast quality. It also details how physical processes are represented in the IFS, and it describes the ways in which observation usage is optimised. The many new products that have been added in recent years are comprehensively discussed, with strengths and weaknesses highlighted. Knowledge of these various aspects allows users to better adapt ECMWF forecast output for their own local purposes.

Until May 2018, the user guide was available to download from ECMWF’s website as a PDF document. Now in web-based format, this new edition will be updated swiftly as the IFS, the products and our understanding evolve. In future, we are aiming for the web platform to allow comments and discussions.

The ECMWF Forecast User Guide can be accessed at: