Heavy snow and blizzards resulted from the Beast from the East in February 2018
Five years ago in late February and early March the phrase "Beast from the East" entered the vocabulary of the UK public.
It was a term coined in the media to describe very cold and snowy weather across the UK.
This was the result of an atmospheric disturbance called Sudden Stratospheric Warming and every time this happens, a Beast from the East is forecast.
But incorrectly.
In February 2018 high above the Arctic in the stratosphere, air started to sink and warm up. This led to a change in the regular winds at this level causing them to switch from westerly to easterly (a wind travelling from east to west).
Three weeks later, the easterly winds made their way down to the troposphere which is the area of the atmosphere where the Polar jet stream - a fast moving ribbon of air at 30,000-40,000 feet - influences our weather.
By late February 2018 the normal west to east flow of the jet stream around the Earth changed and was pushed away from the UK, creating big meanders in the fast winds.
This resulted in a big area of high pressure developing to the north of the UK, blocking mild air coming in from the Atlantic.
Think of this like a big boulder being dumped in a stream blocking and diverting the flow of water around it.
With high pressure situated to the north of the UK, easterly winds are dominant.
Position of the jet stream and resulting area of high pressure sometimes seen after Sudden Stratospheric Warming
The door was open to very cold air from Siberia and Russia to flow across western Europe, sometimes picking up moisture from the North Sea and bringing significant snow.
This was dubbed the "Beast from the East".
It brought more than a week of freezing weather across the UK with temperatures down to -12C, heavy snow and strong winds.
Conditions got even worse in early March 2018 with the arrival of Storm Emma.
Rare red Met Office warnings for snow were in force for south-west England, south Wales and parts of Scotland. Around 50cm (20in) of snow fell on the high ground. Coupled with strong winds to create blizzards, it caused travel chaos.
Thousands of schools closed and 17 people died as a result of the Beast from the East and Storm Emma.
Since this period of severe weather we still seem to be obsessed with the Beast from the East and almost every year there is speculation of its arrival bringing the UK severe winter weather.
This becomes even more the case when we have a period of Sudden Stratospheric Warming.
In reality this warming in the stratosphere, even if it is classed as "major" as it was in 2018, does not always result in a Beast from the East. There are a lot of ingredients and atmospheric factors that would need to link the two.
Snow covering the beach in Blythe, Northumberland in February 2018
What about a Beast from the East this year?
In early February meteorologists observed major Sudden Stratospheric Warming which was followed by speculation about a Beast from the East coming.
It was far too early to determine whether this would actually happen as it can take around six to eight weeks for changes high up in the stratosphere to propagate to the surface and affect our weather.
However, now we are in early March the effects are here, with a large area of high pressure building and blocking those milder south-westerly winds.
While nothing as severe as the Beast from the East will happen, it is going to get much colder in the coming week.
Northerly winds will bring Arctic air across the UK with temperatures below average and significant overnight frosts.
Snow is also in the forecast, initially around north eastern areas of the UK and while there are still some uncertainties beyond that, snow could affect some southern areas as well.
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