The potential advance in predicting European and North American winters has been described as a ‘major step forward’.
It is hoped it may allow forecasters to offer guidance on winter weather patterns weeks ahead of time.
The system aims to better predict the North Atlantic Oscillation, 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.
The Met Office’s Adam Scaife 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. 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. Details appear in a research paper published in the journal Geophysical Research Letters.