As the UK braces for a heavy snowfall this week, weather experts warn that the chilling weather phenomenon responsible for 2018's 'Beast from the East' could be making a comeback.
The Met Office has issued several yellow weather warnings for snow and ice from today (November 18) until Thursday. An amber snow warning is also in effect on Thursday for parts of Yorkshire and the North East, where up to 25cm (10 inches) of snow could blanket some areas.
But it seems the wintry disruption might just be getting started, as forecasters predict the return of sudden stratospheric warming (SSW) - the culprit behind the notorious 'Beast from the East' snowstorm in 2018.
Despite its misleading name, SSW can usher in freezing temperatures and Arctic conditions to our shores. During the 2018 cold snap, some regions of the UK were buried under as much as 20 inches of snow, reports the Mirror.
Stephen Dixon, a spokesperson for the Met Office, told the Mail that indications point towards SSW occurring towards the end of November, which he described as "very early in the season". He added: "Although we occasionally see such events in November, it is relatively early in the winter for this to be occurring. This suggests that the chances of a cold start to winter is higher than in recent years."
Netweather's meteorologist Nick Finnis has hinted that a Sudden Stratospheric Warming (SSW) event could take place around November 25 and 26. This is due to "due to a significant warming of the stratosphere taking place from the Canadian side of the polar region, which looks to displace the stratospheric polar vortex from its usual home over the arctic towards northern Russia and north-east Europe".
At this point, there are no clear signs that an SSW event this year will result in conditions similar to those experienced in 2018. Dixon stated: "It's too early to be definitive about precise impacts on the UK at this stage."
Finnis suggested: "The UK may see an increased chance of further bouts of colder and perhaps wintry conditions as we end the month and head through December, if the SSW takes place."
However, he was quick to add that "there are no guarantees of colder weather because of a SSW".
According to the Met Office, SSW refers to a rapid increase in temperature (up to about 50C in just a couple of days), in the stratosphere, between 10km and 50km above the earth's surface.
This phenomenon occurs due to changes in the polar vortex, and can cause cold air to rush downwards, impacting the jet stream and potentially creating a blocking pattern which can keep snow and cold locked in place for an extended period of time.