Early polar vortex disruption leaves UK winter uncertain

The polar vortex high above the Arctic has weakened and shifted unusually early in November, with some forecasts showing its winds could reverse by mid-November. The disruption may alter weather patterns across the Northern Hemisphere, but forecasters say it is too soon to know whether it will bring snow or colder conditions to the UK. The polar vortex is a circulation of strong winds in the stratosphere that helps keep cold air near the North Pole. It typically strengthens as winter approaches. Disturbances can weaken it, shift it or, in some cases, reverse its winds in an event known as a sudden stratospheric warming. Such events usually occur later in winter. Met Office climate scientist Jeff Knight said the current disruption appears to be the earliest in 75 years of observations. He said there is not enough evidence to establish a link between the unusually early event and El Niño, which can influence atmospheric waves that affect the vortex. If the winds reverse, the resulting changes could shift the jet stream and increase the chance of blocked weather patterns, with colder northerly or easterly winds and drier conditions. BBC meteorologist Simon King said the changes...