Rare polar vortex could increase UK snow risk this winter

Summarised from 3 outlets · Updated 6 Nov, 11:13 · Archive

A weakened Arctic polar vortex could increase the likelihood of snow across the UK this winter.

The polar vortex, a band of strong westerly winds high above the North Pole that normally traps the coldest air on Earth, has weakened and shifted earlier than usual this year. This type of disruption is known as a sudden stratospheric warming, or SSW, and typically occurs in mid-winter rather than November.

Jeff Knight, lead climate scientist at the Met Office, said the event 'would appear to be the earliest on record looking back over the 75 years we've been observing—with most experts agreeing this is a very unusual event.' When an SSW occurs, it can cause the jet stream to shift, potentially increasing the likelihood of colder, drier weather in northern Europe, including the UK, and raising the chances of snow.

Professor Andrew Perez-Charlton, a meteorologist at the University of Reading, explained that 'the typical response to a SSW is for colder and drier conditions over Europe and the UK.' However, he noted uncertainty about what will happen this time. 'Because we haven't seen a SSW event quite like this before, it is harder to anticipate a cold spell at the moment,' he said.

The polar vortex forms each autumn as Arctic temperatures plummet, creating strong westerly winds in the stratosphere that contain the cold air. When these high-altitude winds are disrupted, warming begins in the stratosphere, setting off the chain of atmospheric changes.

The timing of this November event makes its potential impact on UK weather difficult to predict with confidence, despite the historical precedent for colder conditions following such disruptions.

Rare polar vortex could increase UK snow risk this winter — Image: Swindon Advertiser

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How it is being reported

Rare polar vortex could increase snow risk in Swindon and Wiltshire this winterA rare atmospheric event above the Arctic could reshape weather patterns across the UK this winter.Swindon Advertiser · 6 Nov, 10:34
Rare polar vortex could increase snow risk in Swindon and Wiltshire this winterA rare atmospheric event above the Arctic could reshape weather patterns across the UK this winter.Gazette & Herald · 6 Nov, 10:34
Rare polar vortex could increase snow risk in Swindon and Wiltshire this winterA rare atmospheric event above the Arctic could reshape weather patterns across the UK this winter.Wiltshire Times · 6 Nov, 10:34

In this story: Met Office · University of Reading · Jeff Knight · Andrew Perez-Charlton · Swindon · Wiltshire · UK · Arctic

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