A highly unusual weather event, predicted to occur only once in 250 years, is poised to strike the UK, ushering in bitterly cold winter temperatures.
Known as a Sudden Stratospheric Warming (SSW) event, occurrences typically happen every two extended winters. However, this year, the UK may experience an "extremely rare" triple occurrence of these events.
Professor Adam Scaife, head of long-range forecasting at the Met Office, explained, "Although we have not seen it before, we recently documented the chances of an unprecedented three SSW events happening in one winter." Through extensive research utilizing multiple computer simulations, it was determined that such an event could occur approximately once in every 250 winters.
SSW events are often associated with increased chances of cold and dry weather, with 70% of occurrences linked to cold snaps. One notable instance was the "Beast From the East" snowstorm in 2018, which resulted in 17 fatalities.
Professor Scaife further elaborated, stating, "Although this is very rare, we also found that the chance of multiple SSW events is increased… and so the chance of multiple events this winter is raised."
Despite the significance of SSW events, they typically occur high above the Earth's surface, up to 50km into the atmosphere, making their effects less noticeable on the ground. The Met Office explained that when an SSW occurs, it disrupts the normal westerly airflow in the atmosphere, causing the jet stream to meander more, potentially leading to the formation of a large area of high pressure over the northern Atlantic. Photo by Andy Beecroft, Wikimedia commons.
