'Unusual' polar vortex could have unexpected impact on UK as scientists warn 'we’ve never seen anything like this before’
Scientists have spoken out about the 'unusual' polar vortex which could have an unexpected impact on UK due to major changes in the stratosphere.
Winds circulating above the North Pole are splitting into two, which is pushing Arctic air towards Britain and parts of Europe.
The polar vortex is a band of strong winds that remain high in the atmosphere, keeping the trapped air near the North Pole, but when it weakens and breaks up there is a risk of it pushing colder air to the south.
After some of the hottest days on record this summer, and fears about the El Niño phenomenon wreaking havoc on weather and vital food production globally, sparking stockpiling warnings, exactly what's in store for us this winter still can't be confirmed just yet.
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However a weather phenomenon called 'sudden stratospheric warming (SSW)' is currently also developing, created due to the difference in freezing Arctic and warmer areas further south.
This could could cause a huge impact on the weather this winter, as weather patterns lower down in the atmosphere push upwards and interfere with polar vortex winds, meaning temperatures high above the Arctic can change dramatically.
This is also impacted directly by the El Niño event, which sees Pacific sea-level temperatures rise and releases large amounts of heat and energy into the atmosphere and alters atmospheric circulation.
UK could face winter drought
Now, a professor at the University of Reading has warned that prolonged dry weather following the sudden stratospheric warming could actually have a major impact on the UK and its water by preventing reservoirs from refilling over winter.
Professor Andrew Charlton-Perez, a meteorologist, is a researcher on changes in the Arctic stratosphere and the impact of sudden stratospheric warmings on UK weather and forecasts.
He explained that the UK could be colder - but also drier this winter, which could impact water levels after a record-breaking dry summer.
Severe drought remains in parts of Cornwall, Devon, Dorset, Somerset, and East and West Sussex.
"An SSW normally means the UK is, on average, colder and drier, with more settled conditions and often blocking high pressure," he explained.
"Because this is so early in the season, I think snow now in the UK is unlikely, and the forecasts don't currently suggest it.
"There is still too much heat in the oceans, land and atmosphere left over from summer to make snow likely. Later in the winter, the link between an SSW and snowy weather would be stronger.
"Perhaps a bigger concern would be a long dry spell. Our water resources in some parts of the UK are very low after an exceptionally dry and warm summer.
"Some parts of the UK are still in drought or even severe drought, and we need more than 120 percent of our usual rainfall every month over the winter to come out of it.
"If this event or other SSW events during winter bring prolonged periods of dry weather, it could stop our reservoirs from refilling over the winter. That could have extremely significant impacts on water supplies for homes, businesses and farmers next summer.”
'We've never seen anything like this'
Scientists also say they have 'never seen anything like this', with the Polar Vortex collapsing early and marking the earliest sudden stratospheric warming (SSW) event ever recorded in modern observational history.
Professor Charlton-Perez said while it's too early to know how it will impact us throughout winter, the SSW is occurring earlier than normal.
"We've never seen anything like this before," he sad. "Our best records go back to 1979, when satellite observations began, and we have reasonable records back to the 1940s.
"In all that time, we haven't seen a sudden stratospheric warming earlier than very late November.
"This is unusual because the polar vortex has to form first, before it can it interact with the atmospheric waves that travel up from the lower atmosphere, and those waves are what cause these events to occur.
"Our records are relatively short and SSWs are still quite rare, only usually happening about once every two years, but this is certainly new territory from what we know.
"It's too early to say whether the current record strong El Niño event in the Pacific is the cause of this without more analysis. El Niño usually weakens the vortex and can make an SSW more likely in late winter, during January or February.
"But the vortex was not unusually weak before this event began. It is still so early in the colder seasons for the northern hemisphere that the vortex hadn't had much time to form or be impacted by the effects of El Niño."
Topics: Weather, El Niño, Science, World News, UK News
James Holt
