The study looked at how well global weather forecast systems predict uncertainty in forecasts. They analyzed data from 2015 and compared it to data from 2012. Most systems didn't change much, except for the UK Met Office's system which improved in some areas but got worse at predicting certain features. All systems struggled with long-range forecasts due to problems with predicting large-scale weather patterns. Two new methods were tested and found to accurately predict how reliable the forecasts are and the maximum forecast error.