Annual Seminar 2019

The S2S database, a key component of the World Weather Research Programme (WWRP)/World Climate Research Programme (WCRP) Sub-seasonal to Seasonal Prediction Project science plan, opened to the public in 2015. It contains sub-seasonal (up to 60 days) forecasts, 3 weeks behind real time, and reforecasts from 11 operational centres, modelled in part on The Observing System Research and...

Skillful, useful predictions of the climate system beyond the deterministic limits of weather must be built on a basic scientific understanding of predictability and the physical processes giving rise to predictability. Rigorous evaluation of prediction systems is also necessary to understand our current prediction capabilities and identify avenues for improvement. Finally, prediction...

The Copernicus Climate Change Service (C3S), implemented by ECMWF on behalf of the European Union, has developed a seasonal forecast component which has now reached operational status. Based on a multi-system framework, this component of the service offers data previously not widely available, and has proven very popular with users. In addition to a large volume and variety of seasonal...

Substantial progress has taken place in the development of subseasonal and seasonal climate forecast systems. Operational systems now provide a comprehensive set of forecast products, often using the multi-model approach, and a consistent set of forecast quality metrics. However, there are still important gaps in illustrating the applicability of the forecast information. While the advent of...

Extremely strong and weak phases of the stratospheric polar vortex are known to affect the North Atlantic Oscillation and therefore mid-latitude weather. Troposphere–Stratosphere coupling thus provides an important source of predictability for winter forecast on subseasonal to seasonal timescales. However, the exact mechanisms are still unclear and their representations in climate models vary....

As sub-seasonal to seasonal predictive skill is determined by all components relevant for weather and climate prediction, namely initial conditions, Earth-system model components and forcings, it can serve as a driver for joint developments across both communities. Such developments consist of both science and technology elements, and they become rather challenging when aiming for future...