Experts give update on whether polar vortex could hit the UK this autumn

Freezing temperatures and unsettled conditions could sweep the UK as the El Niño weather phenomenon continues to wreak havoc on global weather.

Experts are predicting a wet and stormy autumn that could develop into an icy winter after the “super El Niño” smashed global benchmarks to become the strongest event in history.

The Met Office said the “unprecedented” phenomenon, which has already helped push temperatures to reach the hottest summer on record, will continue to have “far-reaching” implications for weather conditions across the world.

But while a peak in El Niño can weaken the stratospheric polar vortex, experts have warned it’s too soon to tell if this will send freezing arctic air further south this autumn and winter.

The forecaster said “it was too far away to give any forecast information” about whether a polar vortex could impact the UK and it remains “just one possible outcome dependent on many competing factors”.

El Niño is a naturally occurring climate phenomenon that develops in the tropical Pacific Ocean. It takes place when sea-surface temperatures across the central and eastern Pacific become significantly warmer than average, altering atmospheric circulation patterns and influencing weather around the globe.

While wetter weather is expected to move in, the UK just marked its fourth warmest September on record as the anomalous heat that hit the country this summer continues.

After three quarters of England was plunged into drought over the summer, Scotland has seen over a third more rain than its average for September, while southern England remained relatively dry compared to average – despite some recent rain.

Professor Adam Scaife, head of long-range predictions at the Met Office, said: “We have been signalling for months that the developing El Niño will be an unprecedented event. The fact that it has already exceeded previous records – with several weeks to go before it peaks later this year – shows the enormity of this El Niño.

“Scientists are still assessing whether the impacts will be in proportion to its magnitude, but we are already seeing expected effects worldwide.”

Forecasters warned the phenomenon could disrupt a large, high-altitude ring of swirling cold winds spinning above the Arctic known as the stratospheric polar vortex. These disruptions can weaken the jet stream, sending severe, freezing Arctic air plunging southward into North America and Europe.

However, if this happens, it is more likely to trigger freezing temperatures later on in winter, meaning a polar vortex remains unlikely to sweep the UK this autumn.

The Met Office said that over the coming season, the phenomenon is likely to cause “wetter and stormier conditions” that could develop into “cold snaps” over the winter.

The early winter period could be “milder than normal”, the Met Office has said. But as El Niño peaks, the latter part of the season could see the stratospheric polar vortex weaken, leading to an increased chance of Sudden Stratospheric Warming, making cold weather more likely.

British Gas has issued advice in the likelihood of heavy snowfall, advising customers to improve their insulation, protect their pipes, remember where their stopcock is and stockpile at least three days’ worth of food and essentials in an easy-to-reach part of their home.

The forecaster warned that as significant as El Niño is, it can’t determine precise weather patterns and other outcomes are possible.

The agency’s long-range forecast predicts “changeable” conditions as Atlantic frontal systems bring spells of rain, showers and occasional strong winds. But they said temperatures are expected to be above average for the period as a whole.

For the second half of October, showers or longer spells of rain are expected with the wettest and windiest weather in the northwest, drier in the southeast.

There is a chance that a period of more widely dry conditions could develop for a time, but confidence in the details of this is low. Temperatures are expected to be above average overall.

Experts said every El Niño is different, so it is currently impossible to predict the impact of the weather system over the winter.

They added they will continue to monitor the El Niño “as it evolves” and warned that in the long term, it is likely to push up global temperatures in 2027 to new record levels.

Met Office scientist Dr Nick Dunstone explained: “During large El Niño events, significantly more heat is released from the ocean to the atmosphere leading to an increase in global average temperature, particularly in the calendar year following the winter peak of the El Niño.

“Hence, 2027 is very likely to replace 2024 as the warmest year on record and be yet another year to temporarily exceed +1.5 C above the pre-industrial period.”