It’s the sequel that no one wanted.
The weather process that drove the Beast from the East to Britain last February is brewing again and could open the door for a similar icy misery to hit the country again, the Met Office has warned.
The process, known as a Sudden Stratospheric Warming (SSW) of the atmosphere, is a rapid temperature jump high in the atmosphere and is often linked to periods of unusually cold weather, the Met Office said.
As a result, The Met Office has predicted an increased likelihood of cold weather being established across all of the UK from the end of January and into early February, with temperatures continuing a downward trend to become cold or very cold. This would bring a greater risk of snow, ice and widespread frost, particularly across northern parts of the country.
The Met Office said:
“The term SSW refers to what we observe – rapid warming (up to about 50 °C in just a couple of days) in the stratosphere, between 10 km and 50 km up. Jet streams high up in our atmosphere, in both the northern and southern hemisphere, circumnavigate the Earth from west to east. One of these, the Polar Night Jet, circles the Arctic.
“We normally expect our weather to come in from the west – with a flow of relatively mild air coming in off the Atlantic.
“When an SSW brings easterly winds this tends to alter our weather patterns slightly, weakening areas of low pressure and moving our jet stream further south. This leads to high pressure over the North Atlantic, ‘blocking’ that flow of mild Atlantic air and dragging in cold air from the continent to the east. Exactly how cold it might be depends on the details of where the air comes from.
“SSWs don’t always result in this outcome – but a cold snap follows more often than not, so the SSW greatly increases the risk of wintry weather.”
Also published on Medium.