Julia Danzer, University of Graz, Graz, Austria, Marc Schwaerz, University of Graz, Wegener Center for Climate and Global Change (WEGC), Graz, Austria, Gottfried Kirchengast, University of Graz, Wegener Center for Climate and Global Change, Graz, Austria and Sean Healy, European Center for Medium-Range Weather Forecasts, Reading, United Kingdom