Calculations of anticipated differences between real-time and final PCN indices. E _M (blue line) and IMF B _Y (red) in top field (OMNI data). Three-day medians (green) of X and Y components, extrapolated 3-day medians (red) and smoothed median values (magenta) are displayed in the middle fields. Differences between real-time and final PCN values are shown in the bottom field for each day separately.