As the 'big flight' looms Father Christmas is going to be filing his flight plans and checking the weather as here, Rudolph and the rest of the reindeer head around the world.

No-one knows his exact route (or at least I don't think they do), but we'll assume he's making a direct flight from the North Pole, via Lapland and into the UK.

He's got a mild start to his flight in Lapland. Surface temperatures around midnight are shown at close to freezing.

It's dramatically colder as he gains height, and I'm assuming an average flight levels around 20,000ft (Fl200). Temperatures across southern Scandinavia are close to -35C, so certainly thermals will be needed here.

As he gets closer to the UK he has the jet stream to contend with. Winds speeds here are blowing around 170kts from the northwest so one heck of a cross wind to deal with. He'll be adding plenty of correction to his heading and hopefully will power up to climb above the jet stream quickly. As you can see fro the chart below, the winds in the jet stream then eas as he gets coser to our shores, although it'll still be powering through in Shetland and Orkney.

Temperatures in the UK actually rise during the night through the early hours of Christmas Day. You can see below double figure temperatures already spreading northwards.

Visibility will be reduced by rain over western Scotland, western Wales and western England as well as Ireland. heaviest of the rain in western Scotland, but the rainfall forecasts shows drier weather east and south.

Whatever the weather tonight, Santa will be able to cope but I'm sure the extra mince pies will be very welcome; oh, and a carrot for Rudolph!

Merry Christmas!