Status:Finalised Material from: Linus
Discussed in the following Daily reports:
During the first days in June River Seine was flooded. The flooding culminated in Paris late on 3 June with a raised water level of 6.3 metres, being the highest level since 1955.
2. Description of the event
The large-scale flow during the end of May had a Scandinavian blocking event with a cut-off low over western Europe.
The plots below show the 24-hour accumulated rainfall (06z-06z) from HDOBS for the week running up to the peak of the flood. Several days were really wet in northern-central France but the worst day was 30 May with many station above 40 mm and some over 60 mm in the Seine catchment.
3.1 Data assimilation
The plots below shows the verification of the precipitation 30 May 06z to 31 May 06z for HRES forecasts (observations in the first panel).
The plots below show the EFI and SOT for precipitation valid 29 May to 31 May (72 hours). At least from 26 May a strong signal was present and from the 24 and 25 May the areas of high EFI values were shifted somewhat east.
3.4 Monthly forecasts
The plots below show the verification of weekly precipitation anomalies for the weeks 23 May - 29 May (left) and 30 May - 5 June. The first panel is the precipitation in analysis and the rest are forecasts valid for that week.
3.5 Comparison with other centres
The plots below show the return period of the flow in Seine for the point 48.83N/2.27E, which is close to Paris. The forecast gave an early warning of an extreme event. Unfortunately the ensemble clearly missed the event in the forecast from 31 May.
4. Experience from general performance/other cases