Met Office unveils new long-range winter forecast system

Farmers could soon benefit from improved long-range weather forecasts for winter thanks to a breakthrough by scientists.

It follows the development of a new long-range forecasting system hailed as a “major step forward” in predicting extreme weather more accurately in winter.

The system, developed by Met Office scientists, has delivered a potential advance in the skill of predictions for European and North American winters.

It is hoped the new model will help forecasters predict winter weather patterns several weeks ahead of time.

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The system aims to better predict the North Atlantic Oscillation (NAO), which describes differences in air pressure over the ocean between Iceland and the Azores, and it is a basic measure of the strength of the jet stream.

The NAO is an important factor in determining the difference between cold, dry winters and mild, wet and stormy winters.

It largely governs wind strength, number of storms, the number of extremely cold days and winter rainfall patterns.

A better forecast for flooding and storm damage would benefit farming and help safeguard energy supply and transport infrastructure.

Adam Scaife, of the Met Office, said: “This is not a silver bullet for providing forecasts of weather on individual days months ahead, but it is a big step forward in our efforts to better predict the risk of disruptive winter weather weeks ahead.

“As with any long-range forecast, even the new system can only deliver forecasts of the risk of different types of winter conditions.

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“Seasonal forecasting remains a science challenge and we will still see occasions where winter weather does not match the most likely forecast scenario. Nevertheless, this is a major step forward and underlines our confidence that further research can deliver even greater benefits.”

The forecast system is based on the highest resolution climate model in operation in the world, which is the result of years of development by Met Office scientists.

In tests, the computer model looked back at the past 20 winters, including the extreme winters of 2009-10 and 2010-11 as well as the mild, stormy winter of 2011-12, and predicted the weather with 62% accuracy.

The Met Office believes the model could be refined to predict winter weather at 80% accuracy.

Dr Alberto Arribas, who helped develop the forecasting system, said: “The forecasts are very computer intensive and this currently limits forecast accuracy.

“In time, we hope to be able to improve accuracy further as technology advances and we continue to develop this vital area of science.”