The polar vortex just broke a new record but experts aren't sure what it means for this winter's weather

Because the stratospheric polar vortex operates at a global scale, disruptions and reversals can have impacts right around the world - increasing the possibility of cold weather, ice and snow in many regions, including North America.However the possible impacts of this major SSW on the USA and Canada are, as in the UK, very uncertain.There are historical examples of cold, snowy spells that can be linked - at least in part - to polar vortex disruptions.The deadly winter storm that swept as far south as Texas in February 2021 followed a major SSW event that took place the previous month. Widespread snowfall in February 2018, external was also linked to shifts in the polar vortex, and the same goes for the record 'snowmageddon' event that brought record-breaking snow to Washington DC in February 2010 - a winter when the vortex was unusually weak.What these examples have in common is that they occurred in late winter - when polar vortex disruptions are most likely.The difference this time is that the SSW has taken place unprecedentedly early - in the autumn - so its expected impacts are even less certain than normal.Even if widespread northerly winds were to develop, the Arctic has not yet become as bitterly cold as it will be by late winter, so any chill spells may well be somewhat muted.We are currently heading towards the expected peak of the strongest El Niño on record.El Niño is a natural weather pattern that develops in the Pacific Ocean and the atmosphere above it. When the winds that typically blow east-to-west weaken or reverse, warmer water can spread across the central and eastern tropical Pacific leading to changes in atmospheric conditions.It is no surprise that the regions that see the most obvious weather impacts are the areas bordering this part of the Pacific, such as Peru and Ecuador in the east and Australia and Indonesia to the west.However, El Niño can also affect weather patterns much further away.In the UK, it means we tend to see a higher chance of wetter and stormier conditions in autumn and early winter. There is also a higher chance of colder wintry weather developing late in the winter.In the US and Canada there can be a greater chance of a warm and dry winter in northern areas and more risk of flooding rain further south.There is also some evidence that El Niño can increase the likelihood of disruption to the stratospheric polar vortex which can, in turn, bring snowfall later in winter.