The jet stream's influence on extreme storms

Dr. Christian Franzke, of British Antarctic Survey
A new analysis of Europe’s extreme storm events reveals that they often occur near the jet stream – the fast flowing air currents that flow high in the Earth’s atmosphere.

The study further reveals that storms also bunch together in time – with extreme events sometimes happening closer to each other than traditional weather predictions would suggest. This bunching can then have a knock-on effect of leaving a larger gap than predicted between those events and the following storm cluster.

In a paper published this week in a special issue of Philosophical Transactions of the Royal Society A, Dr Christian Franzke, of British Antarctic Survey, examines the impact of the North Atlantic jet stream on extreme wind speeds and storms in Europe.

The impact of natural hazards that can cause significant damage in economic and human terms is of great interest to Government, business and society. European wind storms rank as one of the major causes of global natural catastrophe insurance losses.

The scientific community strives to improve models and predictions. This requires a deep understanding of the pattern and frequency of extreme storm events.

Dr Franzke’s analysis of weather station and satellite data for the North Atlantic and European region between 1958 to 2001 leads him to conclude that the jet stream exerts an influence on wind speeds and that the clustering of storms in time is not just down to coincidence. He says,

'The point was to see if the bunching together of extreme storms is more than just due to chance like a roll of the dice - to see if there is a systematic process leading to clustering. I wanted to find out what might be considered to be the ‘normal’ pattern and see if there was a connection between storms and the jet stream. The data show that storm clusters often follow the track of the jet stream. This is a new step forward in our understanding of this complex and complicated process. This research will help forecasting future storm events and is particularly important because we expect to see an increase in the intensity of storms due to climate change'.

British Antarctic Survey