Preprint of paper Visualizing Confidence in Cluster-based Ensemble Weather Forecast Analyses, published in IEEE Transactions on Visualization and Computer Graphics, vol. 24, no. 1, pp. 109-119, Jan. 2018. doi: 10.1109/TVCG.2017.2745178 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8019883&isnumber=8165924