A professor and meteorologist has identified his main worry about the impact of the polar vortex on the UK — and it's neither snow nor climate change. The polar vortex is dominating headlines across the globe right now due to "unprecedented" shifts in its behaviour.
These shifts have sparked concerns about "weather chaos" descending upon the UK, with heavy snowfall, bitter cold and even worries that gas supplies might be depleted. Weather specialists say "we've never seen anything like this before" regarding the polar vortex and its unusually early weakening this year, referred to as sudden stratospheric warming (SSW).
Professor's main concern: lack of rain
However, Professor Andrew Charlton-Perez, a meteorologist at the University of Reading who studies changes in the Arctic stratosphere and the impact of sudden stratospheric warmings on UK weather and forecasts, says snowfall isn't his principal concern. He told the BBC the "concerning thing would be if this event ends up bringing the typical drier weather pattern and lack of rain".
With the majority of England and Wales still experiencing drought following a historically parched and scorching summer, the persistence of dry conditions poses a real worry for refilling reservoirs. The summer of 2026 was the hottest ever recorded, with rainfall also hitting record low levels, although the impact was not felt equally across all parts of the UK.
The peak temperature recorded this summer reached 38.2C (100.6F) in Gloucestershire on August 13. There were five separate widespread heatwaves, and temperatures of 30C or above were logged on 40 individual days.
Unprecedented early weakening
Prof Charlton-Perez warned that the continued dry conditions brought about by the polar vortex were of greater concern than the possibility of snowfall. Commenting on the polar vortex and sudden stratospheric warming, he said: "We've never seen anything like this before. 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."
Yet despite widespread concerns over colder, snowier conditions, he said: "An SSW normally means the UK is, on average, colder and drier, with more settled conditions and often blocking high pressure. 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% 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."
What is the polar vortex?
The polar vortex is the belt of powerful winds that forms each autumn as Arctic temperatures drop, circulating around 18 miles (30km) above the Arctic region. Annual atmospheric shifts trigger warming high in the atmosphere, referred to as sudden stratospheric warming (SSW), which subsequently weakens the vortex winds. This year, they have diminished unusually early (most SSW events occur from mid-winter onwards).
These changes, in turn, affect the jet stream's positioning, raising the likelihood of a weather system becoming stuck in place, which can lead to drier, colder conditions and heighten the risk of snow.
Prof Charlton-Perez said: "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."
