If you looked at Elexon's wind generation page this morning, you would have seen what appears to be a spectacular forecasting failure. A day-ahead forecast of roughly 16.7 GW. Metered output of 12.6 GW. A gap of more than 4 GW, holding open all day.
It is one of the biggest gaps in five years of data — the 37th worst day out of 2,071. And it has essentially nothing to do with forecasting.
It is, however, on course to be the most expensive day of constraint management in at least the five years I have data for — including, once you adjust for inflation, the worst days of the 2022 energy crisis.