How will it impact us? Signs of a weakening polar vortex

A band of intense winds over the north pole known as the polar vortex is showing signs of weakening, with a direct impact on the UK and Ireland.

At an altitude of around 30 miles, temperatures over the North Pole are currently taking a huge leap upward; from below -60C, the air will warm up to above freezing point this week. As this happens the vortex weakens.

The polar vortex is a high-altitude low-pressure system containing very cold air that plays a major role in atmospheric circulation and thus has a direct influence on our weather.

We can see a strong, stable vortex or a weak, disrupted vortex.

During a disrupted vortex, warm air from the south impacts the jet stream, creating weak points where cold air can travel south impacting the weather here in the UK and Ireland.

A strong vortex often means a strong jet stream delivering mild weather. A weak vortex, and therefore jet stream, brings more winds from the north and east, dragging cold air from the Arctic and Europe to our shores.

Occasionally the vortex can collapse entirely during a sudden stratospheric warming (SSW) event. The probability of this happening now is low but possible.

The so-called ‘Beast from the East’ in 2018 was a result of an SSW bringing heavy snowfall across the country and below-freezing temperatures.

You can keep watch on how changes to the polar vortex are influencing temperatures here with our TemperatureRadar.