The persistent grey and gloomy weather this autumn is being caused by a meteorological phenomenon known as 'anticyclonic gloom', according to the Met Office. This high-pressure system is set to dominate the UK's weather for the week ahead, bringing a lack of blue skies and sunshine.
Anticyclonic gloom occurs when a high-pressure system, or anticyclone, settles over the country. During such periods, air sinks towards the ground, trapping a thin layer of moisture or low cloud close to the surface, sometimes accompanied by drizzle. In summer, the sun is strong enough to break up this low cloud, but in October, reduced solar strength means the cloud remains stubbornly in place.
The phenomenon can also lead to higher pollution levels, as pollutants become trapped under the cloud layer. The Great Smog of 1952, which covered London in a thick, polluted fog and killed thousands, was an extreme example of this effect.
While most of the UK is under grey skies, higher ground such as the Pennines and Scottish Highlands can rise above the low cloud into clearer air. The Met Office reported extraordinarily low humidity of just 4% over the Pennines earlier this week, with beautiful, clear skies.
The rest of the UK will have to wait until Friday for some breaks in the cloud, particularly in the south, western England, West Wales, and northern Scotland. The high pressure is expected to shift into the North Sea over the weekend, allowing winds from the south to bring a breeze and reduce gloomy patches. Saturday is forecast to be generally dry, but wet and windy weather may move in from the west from Sunday.
