The slippage is expected to be at its worst in the afternoon and into the evening. In some places it can be invisible.
— It is sometimes called black slip. It’s not a meteorological expression, but it means that the roads look dry, it’s very treacherous, says Lars Knutsson, meteorologist at SMHI to TT.
The reason is that parts of the affected areas are expected to receive rain. The temperature at the road surface rises more slowly and can be below freezing when the rain hits it. Then the rain freezes and it becomes slippery quickly.
During the day, Dalarna is expected to be hit hardest. Towards Sunday evening, the rain can move east over Örebro and Västmanland, says Lars Knutsson.
— Until Boxing Day, the mild air continues further north. Then it may rain even up the southern coast of Norrland, but it is too early to say anything about the slippery conditions, he says.
Christmas Day is not nearly as big a travel day as the days leading up to Christmas, the Swedish Transport Administration previously told TT. Home journeys are more spread out.