Forecasters have warned that the weather phenomenon behind the 2018 'Beast from the East' could return later this month, bringing further snow and freezing conditions to the UK. The Met Office has already issued yellow and amber weather warnings for snow and ice this week, with up to 25cm (10 inches) expected in parts of Yorkshire and the North East on Thursday.
The phenomenon, known as sudden stratospheric warming (SSW), occurs when the stratosphere rapidly warms, disrupting the polar vortex and forcing cold air southwards. Met Office spokesman Stephen Dixon told the Mail that signals suggest SSW could occur near the end of November, which would be "very early in the season". He added: "This suggests that the chances of a cold start to winter is higher than in recent years."
Netweather forecaster Nick Finnis pinpointed November 25 and 26 as possible dates for the SSW, due to "a significant warming of the stratosphere taking place from the Canadian side of the polar region". This could displace the polar vortex towards northern Russia and north-east Europe, increasing the likelihood of cold, wintry weather in the UK.
However, both forecasters caution that it is too early to predict the exact impacts. Dixon said: "It's too early to be definitive about precise impacts on the UK at this stage." Finnis added that while the UK may see an increased chance of colder conditions as November ends and December begins, "there are no guarantees of colder weather because of a SSW".
The Met Office explains that SSW involves a rapid temperature rise of up to 50°C in just a couple of days in the stratosphere, 10-50km above the Earth's surface. This can cause cold air to rush downwards, affecting the jet stream and potentially creating a blocking pattern that locks snow and cold in place for an extended period.
