The polar vortex has weakened in recent days, raising the prospect of plummeting temperatures, snow, and frost across Britain far earlier in the season than typically expected.
High winds above the Arctic usually circle the North Pole and trap some of the coldest air on Earth. Their weakening means chilly conditions can slip further south, potentially altering the path of the jet stream that normally protects Europe from much colder weather.
Unprecedented Early Disruption
While disruptions to the polar vortex can be observed during winter months, it is unprecedented in modern times for this to happen early in November. The weakening this early in the season could throw current forecasts into disarray amid greater uncertainty about its impact on the UK.
The weakening has already disrupted the strong polar vortex, creating two circulations and pushing colder air further south. It could also increase the possibility of snow, particularly in eastern Britain.
Sudden Stratospheric Warming Risk
Sudden stratospheric warming (SSW) typically happens from mid-winter, but the sudden weakening shows there could be a reversal of polar winds as early as mid-November. The earliest SSW event was recorded on November 28, 1969, and in 2025.
"It 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," lead climate scientist from the Met Office, Jeff Knight, told the BBC.
El Niño Influence and Forecast
The conditions are not unusual toward the end of winter in so-called normal El Niño years, as warmer air in the Pacific can lead to disrupted weather patterns around the globe. The current record El Niño has sparked unusual weather events much earlier in the year than normal.
There is a risk that Britain could be plunged into a deep freeze toward the end of the month. The Met Office said in its long-range forecast for between November 20 and December 4: "Towards the end of November, whilst confidence is very low in the overall weather patterns, there may be a tendency for the tracks of Atlantic lows to shift farther south.
"Temperatures are likely to be near or above average for much of the period, although colder interludes remain possible, perhaps more especially later in the period."
The Mirror has contacted the Met Office for comment.
