Gillian Young¹, Jutta Vüllers¹, Peggy Achtert², Paul Field³, Jonathan Day⁴, Ewan O'Connor⁵, Ian M Brooks¹, Michael K H Tjernstrom⁶, John Prytherch⁶ and Ryan Neely III¹, (1)University of Leeds, Leeds, United Kingdom, (2)University of Reading, Dept. of Meteorology, Reading, United Kingdom, (3)United Kingdom Met Office, Exeter, United Kingdom, (4)European Centre for Medium-Range Weather Forecasts, Reading, United Kingdom, (5)Finnish Meteorological Institute, Helsinki, Finland, (6)Stockholm University, Dept. of Meteorology, Stockholm, Sweden