A paper published by researchers in the School of Geography, University of Lincoln in the journal “Weather and Forecasting”, identifies factors affecting winter weather in the UK and hence advances the possibility of making accurate seasonal forecasts of winter weather. The study was led by Dr Richard Hall, in collaboration with the University of Sheffield and the Met Office.
The midlatitude regions are well known for their variable weather, making it difficult to predict the overall characteristics of a particular season from some months ahead.
Winter weather patterns over the UK are largely determined by characteristics of the jet stream: a southward displacement of the jet can draw down cold Arctic air over the UK, whereas a more northerly jet tends to steer storms towards the UK, resulting in mild wet winters. Much of the jet stream variability arises from natural atmospheric variability, although a number of factors are capable of giving the jet a “nudge” in particular directions. It is these forcing factors that statistical forecasts can help to identify: EL Nino events, Arctic sea-ice extent and sea-surface temperatures are all factors which can have an influence on the position of the North Atlantic jet, and hence on seasonal weather for the UK.
Dr Hall said in relation to his findings, “The ability to forecast seasonal conditions in advance will be of tremendous benefit to energy suppliers, and the agriculture and transport sectors”.