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3.1 Data assimilation
3.2 HRES
The plots below show 24-hour accumulated precipitation between 17 September 00UTC to 18 September 00UTC in observations (first plot) and short HRES forecasts (12 hours apart). All forecasts missed the localised extreme precipitation in southern Italy. The error could be related to a slight shift to the south of the rainbands around Ianos together with the complex local terrain.
3.3 ENS
The plots below show the EFI for precipitation valid on 17 September, in forecast with 1 day apart. A big jump appeared between 14 and 15 September. The ensemble missed the risk of extreme rainfall on the Italian coast as it kept the extreme over sea.
The plots below show the EFI for wind gusts valid on 18 September. A The big jump appeared between 14 and 15 September is also clear here.
The plot below shows the evolution of the forecasts of maximum wind gusts on 18 September in the box outlined above. The plot includes ENS (blue box-and-whisker), HRES (red dot), model climate (red box-and-whisker) and maximum from observations (green). Note that only a few observations of wind gusts were available. Until 14 September 00UTC the forecasts had not picked up the risk.
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