So we are closing in on being a week away from Christmas. We now have model runs from both the GFS and the ECMWF. We are slowly coming into a reliable time for Christmas day. There will still be plenty of changes between now and then but we should start to get more of an idea in the coming days.
So the good news is that the models are showing cold air sitting across the UK and Scotland. The models have been showing wintry showers moving across the Western Isles. Even moving into parts of England. The GFS and ECMWF are both on board with the cold air across the UK. This has been trending a number of days now. Some bookies have suspended betting for a white Christmas in the UK.
The less good news is some of this mornings computer model runs the 00z and 06z build a high pressure ride in which would act to inhibit the wintry showers and suggestion of low pressure moving in later in the day. But far too early to get into the details. At some points yesterday the models where highlight a number of wintry showers across the Islands.
Just a reminder a white Christmas is a single snowflake falling. So there is no gurrentee or suggestion at this stage that we will see a covering of snow. this below from the Met Office
“The definition that the Met Office uses to define a white Christmas is for one snowflake to be observed falling in the 24 hours of 25 December somewhere in the UK.”
So based on the latest model run information and the trends at this stage I am going to go for a 80% chance of Western Isles White Christmas. ( I have never gone higher then 75% in 8 years of doing this white christmas forecasts.
Next update will be on Friday evening.