Hydrological Products
Product name | Description (established over forecast horizon) | Outputs | Forecast Horizon | Forecast model | Hydrological Models | |
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| Medium-range | Reporting Points | Reporting points where more forecast information is available. |
Coloured reporting points (triangle symbol) denote expected floods to exceed 20-year (purple), 5-year (red) or 2-year (yellow) return period by at least 30%, according to the highest probability of exceedance over the |
15-day forecast horizon as shown in the 'Flood summary for days 1- |
15' layer. |
Reporting point symbols are displayed in three ways, depending on the lead time of the expected peak in the forecast:
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Numbers on the reporting point symbols denote the percentage of ensemble members exceeding the specific return period within the |
15-day forecast horizon for reporting points that have floods in the first 10 days (2-year probability above 30%). The shape denotes rising (upward triangle), decreasing (downward triangle), or stagnant (circle) trend of the ensemble median discharge within the forecast horizon. |
Grey squares represent reporting points with no forecasted flood (i.e. less than 30% probability for the river discharge to exceed the 2-year return period flood threshold). The reporting point marker colours are consistent with the days 1- |
15 flood summary map colours, without the probability of exceedance information (single colour tone). |
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Reporting points where more forecast information is available. Purple/red/yellow points denote river catchment outlets where the forecasted probability to exceed the 20-year (purple) / 5-year (red) / 2-year (yellow) return periods is at least 20%. The severity level, i.e. one of the three main colour groups (yellow/red/purple), is defined by the severity of the 30-day maximum of the daily ensemble mean river discharge values. Numbers denote the probability values (percentage of ensemble members exceeding the specific return period). Shape of the markers denotes rising (upward triangle), decreasing (downward triangle), or stagnant (circle) trend of the ensemble mean discharge within the 30-day forecast horizon. The grey squares represent reporting points with no flood signal, i.e. less than 20% probability for exceeding the 2-year return levels.
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| Map | 15 days | ECMWF-ENS (51) | |||
| Medium-range | 5-Year Return Period Exceedance | Probability of ensemble streamflow predictions [%] to exceed the 5-year return period discharge level at any point in the 15-day forecast horizon.
| Map | 15 days | ECMWF-ENS (51) | |
| Medium-range | 20-Year Return Period Exceedance | Probability of ensemble streamflow predictions [%] to exceed the 20-year return period discharge level at any point in the 15-day forecast horizon.
| Map | 15 days | ECMWF-ENS (51) |
Short-range Medium-range |
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Medium-range Whole |
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15-day forecast horizon | Flood summary for days 1-3 |
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The flood summary map combines the 2- (yellow), 5- (red) and 20-year (purple) |
exceedance probabilities into categorical information. Each of the three flood severities is further divided into three subcategories based on the maximum exceedance probability within the |
15-day forecast horizon ( |
30-50%, 50-75% and 75-100% |
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The reporting points are defined according to the 'Flood Summary for days 1-30' layer.
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The flood summary map combines the 2-, 5- and 20-year exceedance probabilities into a category-based information. It shows where the ENS-max (maximum of the ensemble mean discharge) for forecast days 1-3 (4-10 or 11-30 for the other two versions) is >20-year (purple) / 5-20-year (red) / 2-5-year (dark yellow) return period level. Light yellow indicates where the ENS-max is below the 2-year return period value, but there is noticeable probability (>20%) for exceeding the 2-year return period level.
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There are four flavours, based on the period, one map for the first 3 days (days 1-3), one for days 4-10, one for beyond 10 day (days 11-15) and one for the whole 15-day forecast period (days 1-15). The map for days 1-15 is used in the definition of the reporting points. The reporting point marker colours (severity category) are based on this days 1-15 map and also the dynamic reporting points are generated using this information. The reporting points are defined and characterised for flood signal type according to the 'Flood Summary for days 1-15' layer.
| Map | 15 days | ECMWF-ENS (51) |
Flood summary for days 4-10 | |
Flood summary for days 11- |
15 |
Flood summary for days 1- |
15 | |
| Seasonal range | Seasonal |
outlook | River flow anomaly and uncertainty information for the next 7 months, based on monthly average discharge, for all river pixels over 1000 km2. Detailed information is provided in a pop-up window for reporting points (fixed and basin-representative) with the forecast signal and probability evolution, including the model climatology and water balance of the recent past. Further information about the methodology and products is provided at CEMS-flood sub-seasonal and seasonal forecast product generation methodology.
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Map
Hydrographs
16 weeks
(4 months)
Seasonal Outlook - River Network
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showing forecast signal for individual lead times on rivers Graph of weekly averaged forecast hydrograph (box-plots) with water balance of 6 past months and model climatology reference Probability evolution table with the most recent 7 seasonal forecast runs | Monthly, out to 7 months | SEAS5 (51 ensemble members |
16 weeks
(4 months) | |
| Seasonal range | Seasonal |
outlook - Basins | River flow anomaly and uncertainty information for the next 7 months, based on monthly average discharge, aggregated over 942 predefined river basins. Further information about the methodology and products is provided at CEMS-flood sub-seasonal and seasonal forecast product generation methodology.
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showing forecast signal for individual lead times aggregated onto predefined basins | Monthly, out to 7 months | SEAS5 (51 ensemble members |
16 weeks
(4 months) |
5 Year Return Period Exceedance
Probability of ensemble streamflow predictions [%] to exceed a 5-year return period discharge level.
| Sub-seasonal range | River flow anomaly and uncertainty information for the next 5-6 (depending on which day of the week the model runs) calendar weeks, based on weekly average discharge, for all river pixels over 1000 km2. Detailed information is provided in a pop-up window for reporting points (fixed and basin-representative) with the forecast signal and probability evolution, including the model climatology and water balance of the recent past. Further information about the methodology and products is provided at CEMS-flood sub-seasonal and seasonal forecast product generation methodology.
| Map showing forecast signal for individual lead times on rivers Graph of weekly averaged forecast hydrograph (box-plots) with water balance of 6 past weeks and model climatology reference (black dots). Probability evolution table with the most recent (34-40, depending of the day of the week) forecast runs. | Weekly, out to 5-6 weeks | ECMWF-ENS and ENS-extended combined with 51 members (first 51 members used from the 101 members of the ENS-extended after day15) |
20 Year Return Period Exceedance
Probability of ensemble streamflow predictions [%] to exceed a 20-year return period discharge level.
| Sub-seasonal range | River flow anomaly and uncertainty information for the next 5-6 (depending on which day of the week the model runs) calendar weeks, based on weekly average discharge, aggregated over 942 predefined river basins. Further information about the methodology and products is provided at CEMS-flood sub-seasonal and seasonal forecast product generation methodology.
| Map showing forecast signal for individual lead times aggregated onto predefined basins | Weekly, out to 5-6 weeks | ECMWF-ENS and ENS-extended combined with 51 members (first 51 members used from the 101 members of the ENS-extended after day15) |
Product name | Description (established over forecast horizon) | Outputs | Forecast Horizon | Hydrological Models | |||||||||
| Medium-range | Reporting Points | 30 days Reporting points where more forecast information is available. Purple/red/yellow points denote expected floods to exceed 20-year (purple), 5-year (red) or 2-year (yellow) return period by at least 30%, according to the highest probability of exceedance over the 30-day forecast horizon as shown in the 'Flood summary for days 1-30' layer. Flood peaks expected within the first 3 days of forecasts are highlighted with black border surrounding the reporting points. This also includes those cases when the peak has already passed with receding flow and the highest probability is on day 1. In addition, when flood peaks are expected beyond 10 days and no floods are expected in the first 10 days (2-year probability <30%), then the reporting points are shaded with a greyed version of yellow/red/purple to indicate the longer lead time. Numbers denote the percentage of ensemble members exceeding the specific return period within the 30-day forecast horizon for reporting points that have floods in the first 10 days (2-year probability above 30%). The shape denotes rising (upward triangle), decreasing (downward triangle), or stagnant (circle) trend of the ensemble median discharge within the forecast horizon. The grey squares represent reporting points with no forecasted flood (i.e. less than 30% probability for the river discharge to exceed the 2-year return period flood threshold). The reporting point marker colours are consistent with the days 1-30 flood summary map colours, without the probability of exceedance information (single colour tone).
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Short-range Medium-range Extended Range Whole 30-day forecast horizon | Flood summary for days 1-3 | Map showing the exceedance probabilities for the three severity levels of 2- (yellow), 5- (red) and 20-year (purple) return period, with colour tones defined according to the maximum exceedance probability within the 1-3, 4-10, 11-30 and 1-30-day forecast horizon (three subcategories of 30-50%, 50-75% and 75-100% for each of the three severity levels). The reporting points are defined according to the 'Flood Summary for days 1-30' layer.
| Map | 30 days | |||||||||
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Flood summary for days 4-10 | |||||||||||||
Flood summary for days 11-30 | |||||||||||||
Flood summary for days 1-30 | |||||||||||||
| Seasonal range | Seasonal Outlook - Reporting Points | Reporting points where ensemble hydrographs and probability (persistence) tables for the high (> 80th percentile) and low (< 20th percentile) flow categories are available, displaying the river flow forecast out to 4 months. Please note: The user is advised to evaluate forecast skill for their particular application. | Map Hydrographs | 16 weeks (4 months) | |||||||||
| Seasonal range | Seasonal Outlook - River Network | Maximum probability [%] of high (> 80th percentile) or low (< 20th percentile) river flow during the 4 month forecast horizon. Please note: The user is advised to evaluate forecast skill for their particular application. | Map | 16 weeks (4 months) | |||||||||
| Seasonal range | Seasonal Outlook - Basin Overview | Maximum probability [%] of high (> 80th percentile) or low (< 20th percentile) river flow during the 4 month forecast horizon, provided for 305 global basins. Please note: The user is advised to evaluate forecast skill for their particular application. | Map | 16 weeks (4 months) | |||||||||
| Extended Range | 5 Year Return Period Exceedance | Probability of ensemble streamflow predictions [%] to exceed a 5-year return period discharge level. | Map | 30 days | |||||||||
| Extended Range | 20 Year Return Period Exceedance | Probability of ensemble streamflow predictions [%] to exceed a 20-year return period discharge level. | Map | 30 days |