Skillful prediction of European winter temperature and precipitation can be made as early as the preceding September based on changes in Arctic sea-ice cover, reports a study published online in Nature Geoscience. The findings extend the lead time for European winter weather forecasts to three months, and suggest that Arctic sea-ice variability should be used in seasonal prediction systems.

One of the hurdles facing current climate prediction systems is the predictability of the North Atlantic Oscillation (NAO), the leading mode of atmospheric variability from December to February in the Euro-Atlantic region. The NAO greatly influences the variability of surface temperatures and precipitation in the region, and is also associated with North Atlantic storms.

Javier Garcia-Serrano and Claude Frankignoul identify a strong correlation between autumn sea-ice cover in the Arctic Ocean, particularly in the Barents and Kara seas north of Scandinavia and Russia, and the NAO three months down the line. They show that this link can be exploited to make skilful predictions of European winter weather. The authors report that predictions can be further improved, at the expense of a reduction in lead time to two months, by adding Eurasian snow cover as a predictor.