The Met Office has issued an update on the polar vortex that could cause disruption in London and across the UK this winter. An unprecedented “Godzilla” El Niño event is set to hit the capital, following a record-setting dry and hot summer.
The incoming El Niño, a natural climate pattern marked by warming sea surface temperatures in the Pacific Ocean, could be one of the worst on record, according to experts. A research paper published by the US government's NOAA Chemical Sciences Laboratory concluded that El Niño "tends to promote the breakdown of the polar vortex, especially in late winter."
What is the polar vortex?
The polar vortex is a band of strong westerly winds that circles the North Pole and traps bitterly cold air near the Arctic. A weakened or disrupted vortex becomes "wavy" and allows cold air to spill southward into North America and Europe.
That would make the UK likely to face extremely windy and snowy conditions over the coming months.
Met Office warnings
A Met Office 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."
SSW, which involves warming between 10km and 50km above the Earth’s surface, can cause cold air to rush downwards, impacting the jet stream and potentially creating a "blocking pattern." This could cause cold conditions to stay for the remainder of the year.
Dr Will Lang, chief forecaster at the Met Office, said it was a "subtle shift in the odds" that El Niño would cause havoc in the coming weeks, rather than a certainty. He said: "We are going in with a heightened potential for wet weather, heightened potential for potentially stormy conditions, and that leads through to a heightened potential for flooding."
El Niño impacts
Grahame Madge, a Met Office climate spokesman, said: "The El Niño event is still developing in the tropical Pacific and already it has surpassed the magnitude of previous events including the one in 2015/16.
"Globally, an El Niño event has several impacts, including altering rainfall patterns and increasing global temperature overall.
"There are known teleconnections between El Niño and the UK autumn and winter period. For example, there is a tendency towards a stormier start to autumn and winter and similarly there is a trend towards colder spells at the end of winter."
