How this year’s ‘off the charts’ El Niño could affect UK weather this winter

This year’s El Niño could be unprecedented in strength and “off the charts” of what has been seen in the last four decades, the head of the UN weather agency has warned.

El Niño is a naturally occurring weather phenomenon that occurs when sea temperatures in the tropical eastern Pacific rise 0.5°C above the long-term average.

This can have significant effects on weather around the world, historically increasing the risk of floods, extreme heat, storms and drought.

The World Meteorological Organization (WMO) says sea surface temperatures in the central and eastern tropical Pacific are forecast to record levels during October through December, “reflecting the strengthening of El Niño”.

El Niño impacts are already being felt

El Niño’s weather impacts tend to be most severe in regions such as India, East Asia, South America, parts of Africa and the West Pacific.

Parts of Argentina, Paraguay and Uruguay are already experiencing swelling rivers by heavy rains linked to El Niño – forcing thousands of people from their homes and sending ranchers crumbling to move cattle to higher ground.

Wildfires that have swept across Indonesia’ Borneo island, leaving endangered orangutans struggling to survive, have also worsened this year as El Niño intensifies a prolonged dry season.

Will El Niño affect UK weather?

The UK is thousands of miles from the tropical Pacific and so the weather effects of El Niño tend to be less severe.

“Closer to the UK, we expect the influence of El Niño to start to increase the chances of wetter, stormier conditions for northwest Europe, including the UK, in the coming autumn and early winter,” the Met Office said back in August.

According to the Red Cross, El Niño can also increase the likelihood of ‘cold snaps’ in the UK, which could trigger flooding, power cuts, damage by high winds and snowy conditions.

“These events are something the UK experiences every year,” the charity said.

“While El Niño does not directly cause individual storms, floods or cold weather events, forecasts suggest it could increase the likelihood of some weather patterns that make these impacts more likely.”

The Met office previously warned that a peak in El Niño can weaken the stratospheric polar vortex, which risks sending freezing arctic air further south this autumn and winter.

But 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”.