In our previous Christmas updates, we used the CFS model but as some of the medium range models like the GFS and ECMWF have Christmas Day into view on their projection, we’ll be discussing them too in this update.

To start off this update, let’s have a look at the latest run of the GFS. The GFS shows an area of high pressure anchoring itself to the southwest of the UK on Christmas Day which forces the wind direction to be from a northwesterly. In the northeast indicated by the isobars being tightly packed, there is an area of rain pushing southeast from the northwest of Scotland. This brings some outbreaks of wet weather down to the north and east coasts. Behind this rain, it turns relatively milder with more of an Atlantic influence to the air compared to a day or so ago when colder air pushed down to the UK via a northerly flow. This means that Christmas Day would be fairly cool at first but turn milder later on as the rain makes progress. A touch of frost possible in the south early in the day under clear skies from the ridge of high pressure but too much cloud for most others especially in the north for air frost. Maximum temperatures during the day would be in single figures generally. 

Wouldn’t be a White Christmas for most but there would be the outside chance of some snow on high peaks of the Pennines.

The ECM shows the UK firmly in a westerly pattern but the jet stream is a bit meandered to the south of the country and therefore, not particularly mild conditions. A trough from Christmas Eve pushes eastwards and brings down some relatively cooler conditions for a time during the early morning hours. This would result in a touch of frost for parts with the clearer skies and window of lighter winds. However, by midday or the afternoon, an area of low pressure off the Atlantic would bring some rain into the west of the UK pushing eastwards later on and turning the air milder. Maximum temperatures would be in single figures though.

The CFS shows an area of high pressure extending from the Azores through England to much of northeastern Europe whilst there is low pressure anchored just out to the northwest of the UK. The winds are from a southwesterly direction over Northern Ireland and Scotland giving a relatively mild day with outbreaks of rain pushing in. Maximum temperatures would lie in the high single figures and low double digits. It’s fairly cooler over England and parts of Wales as the winds are lighter and skies would be clearer. However, due to the lighter winds, there would be the possibility of mist and fog developing. It’s very likely that the day would end milder and wetter for all of the country as the ridge gets displaced back into Europe.

Summary

Not a particularly exciting update on any front for Christmas Day, it’s all looking very benign though the three models have different solutions each which is no surprise given Christmas Day is still 10 days away. 

If you want to talk Christmas weather we have a Winter Model output discussion and a more christmassy thread called Weather, Gifts, Traditions. Get involved!

Sean Bruen is a forecaster for Metcast (and Snow Watch). His main interests are historical and long range weather. He LOVES snow (his Twitter account is @SnowbieWx, go figure!) and his favourite season is Winter.