Evaluating operational seasonal forecasts in the extratropics: improvements, challenges, and interesting problems

In this talk I will present some recent work covering different aspects of operational seasonal forecasts in the extratropics. The talk will be framed around an evaluation of operational seasonal forecasts since their inception around 20 years ago, utilising continuous development of operational systems from three major forecasting centres (including ECMWF, of course). This analysis highlights some robust improvements but the North Atlantic remains challenging. I will discuss some recent work evaluating winter teleconnections to the North Atlantic, showing that this is the cause of some persistent signal-to-noise errors and highlighting that deficiencies in model dynamics underpin these issues. Finally, I will discuss some recent work on another interesting problem in seasonal and multi-year forecasting.