This data is from the third generation of Meteosats, which are the European meteorological satellites. A lot like GOES in the north-America. The main improvement is really significant improvement in resolution. The resolution is, depending on the channel, 9 times better than in the second generation. The main improvement in forecasting comes due to better information in the initial condition of the numerical weather prediction, but it is hard to quantify in advance. I'd be surprised if MAE, over the 15 days the prediction spans, would improve more than 0.1 C, if we talk about the raw prediction. There are plenty of things that this data is used for, but I would say that improved nowcast of cloud coverage, and energy production related parameters are likely to benefit most from the improvement in resolution.