EGU2020-10991
https://doi.org/10.5194/egusphere-egu2020-10991
EGU General Assembly 2020
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Assessing reasons for skilful predictions of winter windstorms over the Atlantic/European region

Lisa Degenhardt1, Gregor Leckebusch1,2, and Adam Scaife3,4
Lisa Degenhardt et al.
  • 1School of Geography, Earth and Environmental Science, University of Birmingham, UK
  • 2Institute for Meteorology, Freie Universität Berlin, Berlin, Germany
  • 3Met Office Hadley Centre, Exeter, UK
  • 4College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK

Severe Atlantic winter storms are affecting densely populated regions of Europe (e.g. UK, France, Germany, etc.). Consequently, different parts of the society, financial industry (e.g., insurance) and last but not least the general public are interested in skilful forecasts for the upcoming storm season (usually December to March). To allow for a best possible use of steadily improved seasonal forecasts, the understanding which factors contribute to realise forecast skill is essential and will allow for an assessment whether to expect a forecast to be skilful or not.

This study analyses the predictability of the seasonal forecast model of the UK MetOffice, the GloSea5. Windstorm events are identified and tracked following Leckebusch et al. (2008) via the exceedance of the 98th percentile of the near surface wind speed.

Seasonal predictability of windstorm frequency in comparison to observations (based e.g., on ERA5 reanalysis) are calculated and different statistical methods (skill scores) are compared.

Large scale patterns (e.g., NAO, AO, EAWR, etc.) and dynamical factors (e.g., Eady Growth Rate) are analysed and their predictability is assessed in comparison to storm frequency forecast skill. This will lead to an idea how the forecast skill of windstorms is depending on the forecast skill of forcing factors conditional to the phase of large-scale variability modes. Thus, we deduce information, which factors are most important to generate seasonal forecast skill for severe extra-tropical windstorms.

The results can be used to get a better understanding of the resulting skill for the upcoming windstorm season.

How to cite: Degenhardt, L., Leckebusch, G., and Scaife, A.: Assessing reasons for skilful predictions of winter windstorms over the Atlantic/European region, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10991, https://doi.org/10.5194/egusphere-egu2020-10991, 2020.

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