Status:Ongoing analysis Material from: Fernando, Linus

Discussed in the following Daily reports:

http://intra.ecmwf.int/daily/d/dreport/2015/03/31/sc/

http://intra.ecmwf.int/daily/d/dreport/2015/04/01/sc/

http://intra.ecmwf.int/daily/d/dreport/2015/04/03/sc/

Picture

1. Impact

On the 31 March 2015 a strong windstorm hit north-western Europe.the cyclones was named Niklas.

http://en.wikipedia.org/wiki/Cyclone_Niklas

http://www.bbc.co.uk/news/world-europe-32138213

2. Description of the event

Cyclone Niklas was the third intense cyclone over the last days in March. The figures below show short forecasts (12h) of MSLP and precipitation.

The plot below show 24-hour maximum winds on the 31 March.

3. Predictability

3.1 Data assimilation

3.2 HRES

The plots below show 24-hour maximum wind gusts valid 31 March and MSLP valid at 12z on 31 March.

3.3 ENS

The plots below show the EFI and SOT for winds gusts valid 31 March.

The next plot shows the probabilities of exceeding 10-year return period of maximum wind gusts. The top-left panel shows the verification based on ERA Interim.

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

6. Additional material