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In order to display the information content of these 51 ensemble rank values, we use a simplified anomaly representation. For this, 7 anomaly categories were defined by the 10^th, 25^th, 40^th, 60^th, 75^th and 90^th percentiles, representing 7 categories from 'Extreme low' to 'Extreme high'; for the maps and hydrographs, the three middle category anomalies are combined in a single anomaly. In the forecasts, each of these 7 categories will have a probability value, depending on how many of the 51 ensemble members they contain. To simplify the for the maps and hydrographs, the three middle category anomalies are combined in a single anomaly. 

The overall expected anomaly category of the forecast (one of 5 categories, shown by colours in the river network and basin summary maps and in the hydrograph in the pop-up window; and one of 7 categories (with the middle 'Near normal' one extended into 3), highlighted in the probability evolution table in the pop-up window) is defined by the the mean of the 51 ensemble member ranks (rank-mean), which represents a robust anomaly value without any random jumpiness. In addition, the uncertainty about these anomalies is also defined using the standard deviation of the 51 ensemble ranks (rank-std). Based on this rank standard deviation value, one of three uncertainty categories (low / medium / high) are assigned to the forecast.

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