Hello and welcome to the 4th White Christmas forecast. So Christmas is two weeks today. Still a long way off yet in forecast terms but we are getting closer. Still we are in the GFS time frame so none of the of the other models cover christmas yet. Again I will be looking at trends to get more of an idea what we can expect as we head towards Christmas.
So how are the trends looking towards Christmas. Well recent model runs are highlight that it will be a unsettled period around Christmas but staying cold. This is change from our last update where it was trending more settled.
So the latest full model run we have is the 6z run from the morning. This shows a windy day with gales on Christmas day this morning with heavy spells of rain before becoming drier later. Wintry showers with risk of snow on the 23rd and 24th December based on this model run. Staying cold so we could see some wintry showers on Christmas day based on this run.
Now for comparison the 00z model run from this morning does not develop the area of low pressure as deeply. But low pressure would move close to the Western Isles which would bring spells of rain to the Western Isles. Less windy then the 06z. Now rolling back to the 18z from last night it develops a powerful and intense area of low pressure in to South West England and Wales and it would stay dry for us in the Western Isles.
I hope this highlights the reasons why at this time frame there is so much uncertainty as to what Christmas will bring. What you can see from the last few model runs there is a trend to something unsettled but the colder element stays.
So based on the latest model run information and the trends at this stage I am going to go for a 55% chance of Western Isles White Christmas.