La upcoming weather in the UK may be influenced by La Niña soon, as experts have cautioned about the possibility of strong winds sweeping across the nation. La Niña, the counterpart of El Niño, is linked to intense gusts and alterations in global precipitation and temperature patterns. The World Meteorological Organization (WMO) has stated a 55% chance of La Niña affecting weather conditions starting in September.
Although the arrival of La Niña, meaning “the girl” in Spanish, is not immediate, there is a potential for its development this fall, according to senior forecaster Nick Finnis from Netweather.tv. This phenomenon involves the irregular cooling of water in a significant area of the central equatorial Pacific, leading to global weather changes.
The cooler ocean temperatures and atmospheric adjustments caused by La Niña impact the jet stream, a high-speed air current encircling the Earth from west to east. This alteration can shift the jet stream’s position northward, enabling it to interact with ocean moisture, influence storm paths, and increase precipitation levels.
Different agencies have varying criteria for identifying La Niña, with the Met Office mentioning that sea temperatures often drop 3°C to 5°C below average during such events. La Niña typically brings cooler and drier conditions to the tropical eastern Pacific, but there are also neutral phases when weather conditions align with long-term averages.
The likelihood of La Niña occurring between October and December stands at approximately 60%. Nevertheless, WMO forecasters anticipate above-average temperatures for most parts of the globe. WMO Secretary-General Celeste Saulo highlighted the significance of seasonal forecasts for planning in sectors like agriculture, energy, health, and transport.
Mr. Finnis explained that La Niña’s impact on UK weather is more pronounced in winter and spring, with the autumn months being influenced by active hurricanes in the Atlantic Ocean, adding to the forecast uncertainty in the UK. He suggested that Europe may experience more remnants from hurricanes, leading to either warm and sunny conditions if they move northward over the Atlantic or stormy and chilly weather if they head directly towards the UK.
While La Niña is not an immediate concern, the potential for its development in autumn implies that its global weather effects may not be evident until late autumn at the earliest. Mr. Finnis emphasized that each La Niña event is unique, and not all winters following La Niña behave identically.
As September begins, the UK can expect unsettled and occasionally windy weather, with low pressure systems moving eastward from the Atlantic until mid-month. Temperatures are predicted to be slightly below average initially but are projected to rise above average later in the month. Overall, rainfall is expected to be around average levels.
The WMO’s latest update notes that temperatures are likely to be higher than normal in much of the Northern Hemisphere and significant parts of the Southern Hemisphere from September to November. Rainfall predictions resemble patterns typically associated with a moderate La Niña.