Status: Finalised Material from: Linus
1. Impact
The "medicane" Ianos made landfall on the west cost of Greece on the early hours of 18 September. The National Observatory of Athens weather station in Karditsa central Greece recorded 190.6mm of rain on 18-09-2020. The cyclone also caused heavy precipitation on southern Italy the day before.
2. Description of the event
The satellite images below show the evolution of the cyclone from 16 Sept 12UTC to 18 Sept 06UTC.
The plots below show analyses of MSLP and short forecasts of total precipitation between 16 and 19 September 00UTC, every 12th hour.
The plots below show anlayses of z500 and T850 between 17 to 19
3. Predictability
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.
Real (first plot) and simulated satellite images in forecasts from 17 Sept 00UTC, all valid 17 Sept 12UTC in 9km, 4km and 3km-Explict Conv experiments.
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. The big jump 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.
The plots below show the cyclone feature maps valid 17 September 00UTC. The dots are coloured according to the maximum wind speed within 300 km radius.
3.4 Monthly forecasts
3.5 Comparison with other centres
Below you can find animations of the evolution of Ianos in the ICON regional model from 14, 15 and 16 September from the SEE-MHEWS project (provided by Pavel Khain).
