British scientists have warned residents across the United Kingdom to prepare for heavy rainfall, flooding, and severe storms starting as early as October.
The stormy autumn weather, driven by a powerful Super El Nino climate event, is expected to be followed by a bitterly cold winter across the country.
Dr Amulya Chevuturi, a senior hydroclimate scientist at the UK Centre for Ecology & Hydrology, warned that atmospheric conditions will shift sharply later in the year. "A strong El Nino is likely to increase the chances of wetter, stormier conditions for the UK from October to December," Chevuturi said, adding that the North West is expected to be worse affected than the South East.
The forecast follows months of relentless heat across Britain. Professor Bill McGuire, Professor Emeritus of Geophysical Hazards, cautioned that the autumn storms represent the first stage of a two-part seasonal disruption. "Powerful El Ninos typically bring mild, stormy Autumns and early Winters to the UK, followed by bitter cold, although this isn't set in stone," McGuire said.
Record summer heat and the El Nino mechanism
The warning comes as the UK closes in on historic temperature records. According to the Met Office, the national weather service, Britain is on course to record its warmest summer on record, requiring only average conditions through the remainder of August to surpass the previous high set last year.
However, meteorologists predict a sudden transition to wet and stormy conditions as autumn approaches. The change is linked to the El Nino Southern Oscillation, a naturally occurring global climate cycle that alternates between warm El Nino phases and cooler La Nina phases every two to seven years.
During an El Nino event, the powerful trade winds that normally blow warm surface waters westward across the Pacific Ocean toward Australia weaken or reverse direction. This atmospheric shift prevents cool waters from welling up from the deep ocean off South America, allowing warm water to accumulate along the South American coast. As the warm water spreads out, it alters jet streams and atmospheric circulation, causing major weather disruptions worldwide.
Autumn storm patterns and flood risks
While much of the UK is expected to experience thunderstorms this week, scientists predict the most severe atmospheric disruptions will begin in autumn. McGuire noted that autumn storm activity in the UK traditionally commences in late September or early October.
"In 2024 this began with Storm Ashley on the 20th of the month, and last year with Storm Amy on October 3rd," McGuire said, noting that the current year is likely to follow a similar pattern. He warned that higher average wind speeds, larger gusts, and heavier rainfall would likely lead to increased property damage and higher costs for homeowners, insurers, and the wider economy.
The risk of severe flooding is heightened by current drought conditions across much of England and Wales. Dr Akshay Deoras, a senior research scientist at the National Centre for Atmospheric Science and the Department of Meteorology at the University of Reading, explained how prolonged dry weather exacerbates runoff.
"After an exceptionally dry summer across Wales and England, hard, dry soils may struggle to absorb intense rainfall," Deoras said. "Heavy downpours could therefore run off quickly, increasing the risk of flash flooding, surface water flooding and disruption." Deoras added that strong winds could damage infrastructure and cause significant disruption to transport networks.
Historical storms and winter energy pressures
To illustrate the potential severity of the upcoming weather, climate experts point to previous major climate events. Professor Hayley Fowler, Professor of Climate Change Impacts and Director of the Centre for Climate and Environmental Resilience at Newcastle University, highlighted the impact of the last major event. "The last strong El Nino in 2015-16 produced a series of storms, including the massive flooding from Storm Desmond," Fowler said. "It is likely we will see similar storms this coming winter."
Storm Desmond was a severe winter storm that struck the United Kingdom in December 2015, delivering heavy rainfall and widespread inundation. The storm primarily devastated Cumbria, a mountainous county in North West England, resulting in severe flooding that inundated approximately 5,200 homes and local businesses.
Following the forecast autumn storms, scientists expect weather conditions to shift toward lower temperatures in late winter. According to climate models, the UK weather pattern during an El Nino phase typically brings milder and wetter weather in autumn, increased rain and storm probability in early winter, and very cold, drier conditions in late winter.
Deoras warned that a colder late winter could create additional societal challenges. "A cooler, drier winter could increase heating demand and put greater pressure on energy systems," Deoras said. However, he emphasized that a stronger El Nino does not automatically translate into stronger direct impacts in Britain.
"Its biggest consequences may instead be indirect, as disruption to global agriculture and energy demand feeds through into food prices and energy costs," Deoras added.
