Storm Jocelyn will quickly follow Storm Isha, meteorologists said, continuing what has been the most active storm season in the UK and Ireland since records began.
Met Éireann has named Storm Jocelyn, which is forecast to bring strong winds and heavy rain to the UK on Tuesday and into Wednesday.
The storm season began with Agnes, which brought heavy rain and gusts of 70mph to the UK in late September. This was followed by storms Babet, Ciarán, Debi, Elin, Fergus, Gerrit, Henk and Isha.
The approaching Jocelyn is the second named storm in the space of 36 hours, a strikingly short space of time that is not unusual in itself, said Liz Bentley, the chief executive of the Royal Meteorological Society.
“But it is unusual to have had so many named storms by now,” she said. “Jocelyn will be the tenth named storm since the autumn/winter storm season started. We’ve not got that far into the alphabet in January [before] so it is unusual to have seen such an active run.”
It poses the question of why there are so many storms this year, and how much is it to do with climate change.
The “why” is all down to the jet stream, Bentley said.
She added: “The jet stream is a band of strong wind to the top of our atmosphere, about 30,000ft, and when the jet stream is active it develops these low systems and drives them across the Atlantic towards the UK.
“While the jet stream remains active, we are going to see this unsettled period.”
On what makes the jet stream so active, she said: “There are a number of things happening,” said Bentley. “At the moment, you can look at what is happening in the US, where they have had really cold weather going all the way down to Texas.
“That plunge of cold air going further south has caused the difference in temperature, north and south, to increase. The temperature gradient increases and it is that which causes the jet stream to accelerate.”
Climate change is also playing a role, but the precise effects on this year’s surfeit of storms are trickier to pin down. Experts agree it is important that we gain a greater understanding of this.
“There isn’t a clear signal that climate change is leading to more extreme storms in the UK,” said Bentley. “There is a little bit of evidence, but it’s not conclusive.
“What is happening though is that because of a warmer climate the atmosphere can hold more moisture, so when we get these storms the rainfall tends to be a lot heavier. When you have one storm after another, that’s when we get widespread flooding.”
The UK and Ireland have been naming storms only since 2015 and there does not appear to be an obvious trend. In 2015-16 there were 11 named storms and in 2022-23 there only two, Antoni and Betty, both in August.
“There is variability,” said Bentley. “Some winters have been fairly benign and some winters can be very active, this one in particular.”
Naming UK storms has the aim of improving communication of high-impact weather events. The names this year those of include scientists, meteorologists and other people involved in the weather, as well as public suggestions. Jocelyn is named after the astrophysicist Dame Jocelyn Bell Burnell, while Isha – pronounced e-sha – came from a member of the public.
Anyone, from Atticus to Zelda, can suggest future names by emailling nameourstorms@metoffice.gov.uk.
