Northern parts of the UK could be in store for a white Christmas, forecasters have said.
Scotland, the far north of England and Northern Ireland are the areas most likely to see snowfall to usher in the festive celebrations, particularly on higher ground.
But exactly where the boundary between cold and milder air will be - and therefore which areas might see snow - is still unclear, the Met Office said.
Go here for the very latest breaking news updates from across the North East
Helen Caughey, deputy chief meteorologist at the Met Office, said: "With colder air meeting milder air over the UK, the specific details of the forecast for Christmas Day are still a little uncertain.
"Milder air moves north-east over much of the country by the middle of the week, with spells of rain for most at times, which will turn to snow over higher ground in northern Scotland initially.
"The boundary between the milder and colder air is then forecast to sink south later on Christmas Eve and through Christmas Day, introducing colder, clearer conditions for some.
Conditions are forecast to become more unsettled from Wednesday, with bands of rain expected across the UK.
Sleet, snow and ice are predicted over higher ground in Scotland on Wednesday and snow is expected on Thursday.
Blizzards could be in store in Scotland on Christmas Eve thanks to strong winds, while areas further south are expected to remain mild and cloudy with some rain.
There is also the risk of fog across southern parts of England and Wales on Christmas Eve, which could affect travel.
