The Met Office has said a polar vortex-driven cold snap or snow remains unlikely this autumn, even as this year's El Niño threatens to become the "largest in living memory" and an "unprecedented event."
Forecasters have warned that El Niño – the sudden warming of sea surface temperatures – could disrupt the stratospheric polar vortex, a huge, high-altitude ring of swirling cold winds above the Arctic. A weakened vortex can send severe, freezing Arctic air into North America and Europe.
Cold snap more likely in winter
According to the Met Office, freezing temperatures are more likely to hit later on during winter rather than this autumn.
A spokesperson said: "Through the latter part of the winter, following a peak in El Niño, the stratospheric Polar Vortex can become weaker, leading to an increased chance of Sudden Stratospheric Warming (SSW) events unfurling, increasing the potential for cold weather."
The forecaster said it "was too far away to give any forecast information" about how this might affect the UK, and it remains "just one possible outcome dependent on many competing factors."
Record-breaking El Niño
This year's "super El Niño" has already shattered global records to become the most powerful event in history.
Professor Adam Scaife, head of long-range predictions, 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."
Wetter, stormier conditions ahead
The naturally occurring climate pattern develops in the Pacific Ocean when sea surface temperatures become much warmer than average, impacting weather conditions across the globe, with its effects often peaking around December.
El Niño can lead to significant human impacts affecting things such as infrastructure, agriculture, health and energy sectors, the Met Office warned. In the coming months, it is likely to cause "wetter and stormier conditions" that could trigger flooding and develop into "cold snaps" over the winter period.
