Met Office: polar vortex disturbance could raise the chance of a colder winter in the UK

In a statement dated 4 November 2026, the Met Office described a disturbance of the stratospheric polar vortex above the North Pole. There are signs that a sudden stratospheric warming (SSW) is developing. Some media have linked this to the "Beast from the East", the cold and snow spell of 2018.

What the polar vortex and SSW are

The polar vortex is a system of strong winds circling high above the Arctic. When it is strongly disturbed, the stratosphere above the pole warms. In a so-called major SSW, the westerly winds around the vortex can reverse and become easterly. The name refers to the upper atmosphere, not to temperatures at the surface.

The Met Office notes that this time the disturbance is appearing very early in the season. Meteorologists more often analyse such events in the middle of winter. It points to El Niño in the Pacific as a possible factor, because El Niño winters make SSWs more likely.

How certain is it

According to ECMWF model forecasts, stratospheric temperatures are still rising while the winds around the vortex weaken. Many forecast runs suggest the winds could briefly reverse within the coming week, which would meet the definition of a major SSW. However, the Met Office stresses that the expected reversal is relatively weak and short-lived. It is still unclear whether a major SSW will happen at all.

Even if it does, it does not automatically mean severe frost in the UK. The effects may only be visible after several weeks (according to Polish Express, two to six). Much also depends on where areas of high pressure form. Blocking in the north favours easterly winds, while high pressure to the west favours northerly winds.

The Met Office describes the polar vortex as a factor that can tilt the odds towards certain weather patterns, not a switch that turns cold weather on or off. Experience shows, however, that an SSW raises the chance of colder weather in Britain. Met Office meteorologist Aidan said this chain of events can be flagged well in advance.

What this means for you

For now there is no warning of specific frost or snowfall. It is a signal that winter may be colder than usual, but nothing is certain. It is worth following current Met Office forecasts and warnings, especially before travelling or planning your heating.