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ECMWF launches new Strategy

ECMWF has launched its new ten-year Strategy, which sets ambitious goals that push the limits of predictability in weather forecasting.

A key target is to extend the probabilistic skill of ECMWF’s high-impact weather forecasts by three to six days over the next decade.

This would enable skilful predictions of high-impact weather up to two weeks ahead.

Other goals include predicting large-scale patterns and regime transitions up to four weeks ahead, and global-scale anomalies up to a year ahead.

Other goals include predicting large-scale patterns and regime transitions up to four weeks ahead, and global-scale anomalies up to a year ahead.

ECMWF’s Director-General Florence Rabier said: “Our 2025 ambition raises the international bar. Given the greater likelihood of life-threatening climate change impacts on the Earth’s weather, we will harness rapidly advancing data availability and technology to stretch the accuracy and range of predictions further and faster.

“ECMWF is a shining example of the value of European and global cooperation in the scientific field, and one which has tangible benefits day in, day out for dozens of national economies and millions of people’s daily lives.”

The Strategy was approved unanimously by the representatives of ECMWF’s Member States meeting on 30 June and 1 July.

Two pillars

Turning the Strategy’s goals into reality will require a sustained collaborative effort in two areas in particular: ensemble forecasts and Earth system modelling.

Ensemble forecasts are probabilistic: they provide a range of likely scenarios and give an indication of the confidence forecasters can have in their predictions. Running them at high resolution can increase the skill of forecasts but is computationally demanding.

The Strategy specifies a target of a 5 km grid spacing for ensemble forecasts by 2025, down from 18 km today. This is at the limit of what can be done scientifically and in terms of the computing capacity ECMWF envisages having.

In the context of weather prediction, Earth system modelling means adequately representing the interactions between components of the Earth system that influence the weather. In addition to the atmosphere, these components include the oceans, sea ice and the continental land surfaces.

Earth system interactions will also have to be represented in data assimilation, the process of combining weather observations with model output to achieve the best possible description of the state of the Earth system at the start of a forecast run.

The Strategy makes it clear that ECMWF aims to remain at the forefront of efforts to develop innovative solutions for data assimilation.

Scalable computing

The Strategy sets out how ECMWF intends to meet the computational challenges created by the evolution towards Earth system modelling at high resolution.

It explains that all parts of the forecasting process need to be optimised to ensure that the Centre’s high-performance computing facility remains economically and environmentally sustainable.

To this end, numerical weather prediction and computational science will have to advance in concert towards scalable, energy-efficient algorithms and technology.

Research projects exploring future heterogeneous computer architectures have already been initiated and will remain important throughout the period covered by the Strategy.


ECMWF’s new Strategy has been developed in close collaboration with its Member States. Implementing it will also require working closely with Member and Co-operating States, national meteorological services and the wider scientific community worldwide.

The Strategy also highlights the importance of continued collaboration with partner organisations across the world, including space agencies such as EUMETSAT, to ensure ECMWF receives the weather observations it needs to achieve its goals.

Further information

Press Release ECMWF commits to pushing the limits of predictability in 2025 strategy

The full Strategy 2016–2025 and a more concise Roadmap to 2025 are available on the website’s Strategy page.