Question to the Department for Business, Energy and Industrial Strategy:

To ask Her Majesty's Government what assessment they have made of the impact of the jetstream on recent weather events; and what plans they have to conduct research into the role of the jetstream in extreme weather events.

Extended spells of dry sunny weather during spring are primarily a consequence of the large-scale circulation and buckling of the jet stream allowing for the development of persistent high-pressure systems close to the UK. In spring 2020 the jet stream shifted to the north-west of the UK and successive areas of high pressure dominated the country, leading to sunny, warm and dry conditions. Weather conditions in February 2020 were also due to a change in the jet stream. In this instance, a strengthening of the jet over the UK delivered multiple storms and record rainfall. In both cases, the conditions were predicted in some detail days ahead in Met Office short-range weather forecasts and also anticipated in its long-range outlooks.

The role of the jet stream in influencing UK weather is well understood. The next step is to understand what is driving the behaviour of the jet steam when there are extremes. There is strong evidence from research by the Met Office that global connections from the tropics were responsible for the behaviour of the jet stream during February 2020. Work is ongoing to examine what influenced the jet stream during spring 2020. Future research by the Met Office will examine current variability in the jet stream and the effect on UK weather.