Jet stream data could improve regional seasonal forecasts - researchers
Scientists could come up with better seasonal weather forecasts for different parts of the UK by using data on the Atlantic jet stream, a study has found.
University of Lincoln researchers examined the relationship between changes in the jet stream - a giant current of air flowing eastwards over the North Atlantic - and UK regional winter and summer weather.
Their research published in the International Journal of Climatology looked at where the jet stream was located and how variable it was throughout the year, and compared it to UK temperatures and rainfall over the last 65 years.
The study found that changes to the jet stream were significantly associated with variations in regional rainfall and temperatures in the UK.
A reliable seasonal forecast of jet stream conditions could indicate weather patterns expected over different parts of the UK over the following months, the study found.
The information could help farmers, energy suppliers, transport providers and insurance companies, as well as the public, plan for likely weather conditions.
Seasonal forecasts often focus on a measure known as the North Atlantic Oscillation index, which indicates the position of the jet stream.
"But it does not tell the whole story in terms of regional variations of rainfall and temperature," Dr Richard Hall of the University of Lincoln's school of geography said.
For example, it is a reasonably good predictor of winter rainfall in north west Scotland, north west England, and the east side of the UK, but not for the west country and Midlands, where other factors would need to be used.
Looking at a range of factors, including the latitude and speed of the jet stream, could help forecasters build up better seasonal forecasts on a more regional basis.
The university's Professor Edward Hanna said: "Understanding how jet stream changes affect the nature and severity of seasonal weather on a UK regional basis will make a huge difference to the general public and planners in the transport, energy, construction and leisure sectors - particularly over the winter months.
"If we can predict jet stream changes on a seasonal basis, or even potentially a number of years ahead, we should then be able to better predict seasonal weather changes on a smaller, regional scale than we currently can."
Dr Hall said forecasters could be able to give probabilities for upcoming weather such as wet and stormy winters, to help people make decisions on whether they need to take steps to deal with the likely conditions.