The CEMS-flood sub-seasonal and seasonal products are essentially the same across the two systems and similarly the same across EFAS and GloFAS. Below we introduce the products that available.

River network summary map

The river network summary map layer shows the combined forecast anomaly and uncertainty signal in a simplified way for each forecast lead time (Figure 1a). The lead time is weekly (always Monday to Sunday, with the weekly average river discharge) in the sub-seasonal and monthly (always calendar month, with the monthly average river discharge). The forecast signal is shown for all river pixels above a certain minimum catchment area (currently 50 km² in EFAS and 250 km² in GloFAS). Each of these river pixels are coloured by the dominant anomaly category and the also by the uncertainty category.

There are 7 anomaly categories and three uncertainty categories defined, based on the extremity level of the ensemble forecast members in the 99-value percentile climatological distribution. The details of the computation methodology is described here: Placeholder CEMS-flood sub-seasonal and seasonal forecast anomaly and uncertainty computation methodology.

On the river network summary map only 5 anomaly categories are displayed by combining the middle three into one larger 'Near normal' category. Each of these categories are divided into three sub-categoires by the uncertainty, in total making it into 15 forecast signal categories. Figure 1b shows the assigned colours and the corresponding extremity levels (or climatological percentiles groups). Each of the 5 anomaly categories have a distinct colour, where the three uncertainty levels is indicated by lighter colours as the uncertainty increases.

The river network summary map also contains the reporting points. These are river locations, where detailed information is provided about the evolution of the forecast signal. There reporting points are either fixed points, which are also used in the medium-range flood products and the basin-representative points, which are a one point per basin selected locations for the basin network used in the sub-seasonal and seasonal products. Further details about the basins and the representative points are available here: Placeholder CEMS-flood sub-seasonal and seasonal basins and representative stations.

Example snapshot of the sub-seasonal and seasonal river network summary map with the reporting points.

Reporting point pop-up window

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