Status: Finalised Material from: Ervin, Linus
1. Impact
The cyclone Ellen hit the south-coast of Ireland on 19-20 August. The cyclone seem to have produced 89 mph (143 kph or 40 mps) in Cork (the maximum in land) and also 112 mph was observed by a buoy near the shore. The cyclone seems to have produced a string jet feature around midnight between 19-20 August. You can get further info e.g. from these articles (read1 and read2).
2. Description of the event
The plots below show satellite images every 3rd hour from 19 August 12UTC to 21 August 00UTC.
The plots below show analyses of MSLP and 6-hour precipitation from 18 August 12UTC to 21 August 00UTC. The extreme winds on southern Ireland was due to a small-scale feature inside a larger cyclonic system.
3. Predictability
3.1 Data assimilation
3.2 HRES
The plots below show the 24-hour maximum wind gusts during 19 August 12UTC to 20 August 12UTC in observations (first plot) and HRES forecasts with 12-hours apart. The very extreme winds were captured in HRES 1.5 day before.
3.3 ENS
The plots below show EFI for 24-hour wind gusts valid 20 August.
The plot below shows the evolution of the forecasts for 24-hour wind gusts inside a 2x2 degree box over southern Ireland (see plots above). The plot include ENS (blue box-and-whisker), HRES (red dot), model climate (red box-and-whisker, not added yet) and observations (green dot). There is a big jump in the ensemble distribution between 18 August 06UTC and 18 August 12UTC forecasts.
3.4 Monthly 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
- Good medium-range signal for large-scale cyclone
- The small scale extreme was captured 1.5 days ahead of the event