Status:Ongoing analysis Material from: Tim, Ivan, Linus
Picture
1. Impact
2. Description of the event
The plots below show analyses of MSLP and short forecasts of 6-hour total precipitation covering 26 September 00UTC to 30 September 00UTC, every 12th hour.
The plots below show analyses of z500 (contour) and T850 (shade) covering 26 September 00UTC to 30 September 00UTC, every 12th hour.
Air mass RGB animation from 27 September to 30 September 2018 inclusive.
ECMWF analysis of MSLP and air mass RGB, animation every 6 hours covering the period from 27 September 00UTC to 1 October 2018 00 UTC.
3. Predictability
3.1 Data assimilation
3.2 HRES
The first plots below shows (the few) observations of 24-hour precipitation 29 September 06z to 30 September 06z and the following plots HRES forecasts from different initial times valid the same time. The plots also includes MSLP valid at 18UTC on 29 September.
The plots below show HRES forecasts for 24-hour maximum wind gusts valid 29 September (shade) and MSLP valid 29 September 18UTC (contour).
3.3 ENS
The plots below show EFI and SOT for 24-hour precipitation (29 September).
The plots below show EFI and SOT for 24-hour maximum wind gusts valid 29 September.
3.4 Monthly forecasts
The plots below show the weekly anomalies (24-30 September) of precipitation from extended-range forecasts.
3.5 Comparison with other centres
4. Experience from general performance/other cases
5. Good and bad aspects of the forecasts for the event
- Unusually large differences between DA and LWDA analyses in the vicinity of the incipient cyclone near Libya => late data impact
- IFS probably the first, of the international models, to forecast the genesis of this cyclone
- Some early HRES forecasts were too intense, giving medicanes much deeper than had ever occurred before in the Mediterranean (though not necessarily impossible, theory suggest that a level equivalent to CAT 1 hurricane is possible for a medicane)
- ENS and HRES exhibited similar track errors in the medium range - mostly the tracks were a bit too far south - e.g. near to or just N of Crete
- Ppn forecasts in the medium range were "contaminated" by track errors
- IFS analyses of the system near to Greece were poor, central mslp values ~10-15mb too high. Likewise the core of strong gradients and strong surface winds was notably missing in these analyses
- Better analyses could in principal have been realised by better use of high density scatterometer data. It is probably the data thinning that stops us realising this benefit (though that may have other associated problems).