Which will it be: Beast from the East or return of summer?

Which will it be
Beast from the East or return of summer?

Snow blanketed large swathes of the UK amidst the Beast from the East, including the South Downs as pictured, 28th February 2018.

Headlines are already hitting with news of a Beast from the East, but let's not forget the unseasonably mild October! So which is it?

The end of this week and weekend, from the 6th, will see temperatures rise into the twenties, perhaps reaching the mid-twenties over the weekend of the 7th October.

It will be unseasonably warm for October with temperatures nearly up to 8 degrees above normal for the time of year. But with autumn here and winter on the horizon, it's only natural to be wondering when the cold will eventually settle in.

An Indian Summer?

A period of unseasonably warm, dry weather in autumn, typically after the first frost - though this isn't a formal meteorological term.

Beast from the East?

The Beast from the East is a weather phenomenon first did the rounds in 2018 when an anticyclone, or high pressure system, drove in extremely dry, cold air in February, with heavy snow showers piling in off the North Sea.

The phrase on a more general note though, is used to describe cold and wintry conditions in the UK and Ireland as a result of a polar continental air mass.

This cold and snowy set-up in 2018 was connected to the onset of a Sudden Stratospheric Warming (SSW) event.

Every year in winter, strong westerly winds encircle the pole, known as the Stratospheric Polar Vortex. Sometimes, these winds weaken or can even reverse direction.

This cold air then descends into the troposphere, causing the stratosphere to rapidly warm - Sudden Stratospheric Warming.

It is this change that impacts our jet stream, encouraging a blocking high pressure system to set up over Scandinavia, driving in colder and drier weather to Northern Europe.

A SSW event happens on average every 2-3 years. The lag effect can take several weeks to reach the lower portions of the atmosphere, and just because the warming occurs, doesn't necessarily mean we will see extreme cold.

The arrival of El Niño has also been linked to enhancing the risk of colder winters across the UK, though again, is not guaranteed.

So, will we see the Beast from the East return for 2023/24? Well, there's certainly no snow or weakening of the Polar Vortex in the forecast just yet, but we'll be sure to keep you in the loop when there is!