A white Christmas is looking like not much more than a song title this year, when it comes to the UK forecast.
The traditional festive images of snowfall on Christmas Day is something that eludes the UK – and this year is not looking like it will be any different.
While some snow may fall, it will most likely be restricted to high ground, according to the Met Office, with the chances of widespread snow lying on the ground seeming unlikely.
Long-range predictions from the forecaster – from 22 to 31 December – predict wind and rain in the north over Christmas, with more settled and milder conditions expected in the south.
The Met Office said recent rumours and reports of snow for Christmas are based on “one-off, individual forecasting model runs”, whereas these should be used as one part of a wider range of information to “provide a full forecast picture”.
Met Office meteorologist Aidan McGivern said: “What meteorologists actually do, is rather than cherry pick one computer model run for more than two weeks’ time, the computer models are run lots and lots of times and then we can pick out areas where they are agreeing and areas where they are disagreeing.
“Then we can talk about likely weather patterns and less-likely weather patterns, common themes and so on.”
What is the forecast for Christmas Day?
Weather maps from WX Charts previously suggested that between 6pm on 23 December and 6am on Christmas morning, snow flurries will constantly fall over at least some parts of the British Isles. They also recently predicted a 400-mile snow storm for December in the run up to Christmas.
But the Met Office’s long-range forecast for 22 December to 31 December poured water on those claims. It says: “Likely starting off very unsettled, with blustery showers, a mix of rain, sleet, some hill snow and soft hail being driven in by a strong to gale force northwesterly wind.
“Southeastern areas most sheltered from these but widely feeling very cold. Gradually turning more settled through the following week, with cloud, stronger winds and outbreaks of rain increasingly becoming confined to northwest Scotland, as an area of high pressure becomes established across at least the south of the UK.
“It may even become settled here too, but confidence in the north/south boundary between settled and unsettled gets steadily lower through the period. Becoming widely mild, perhaps exceptionally so in some places, although clearer spells overnight may lead to localised frost and fog.“
A blog post on whether it is likely to be a White Christmas adds: “Yes, our long-range forecast now covers the festive period but, it isn’t a detailed forecast like our five-day forecasts.”
It says the reason why a long-range forecast doesn’t go into too much detail is because the “story is always changing”, adding: “Therefore, whilst our long-range forecast gives a prediction as to what the weather may be doing over the Christmas period, we have to acknowledge that many outcomes remain possible, and it won’t be until much closer to the time that we can say with any more certainty.”
What about New Year?
The long-range forecast for 1 to 15 January refers to changeable conditions – including rain annd strong winds in the north –.and above average temperatures.
But again, it adds: “Colder, brighter, and potentially wintry spells cannot be ruled out, particularly early in the period.”
Why can’t the forecast be more accurate?
Predicting the weather can be a notoriously tricky affair – in fact the Met Office say the “chaotic nature of the atmosphere” stops them committing to accurate forecasts more than five days in the future.
The forecaster relies on more generalised predictions covering the whole country in the longer term as “small events currently over the Atlantic can have potentially significant impacts on our weather in the UK in several days’ time”. They say this leads to a situation where they can get a “general feel” of the weather but not issue solid predictions due to the changing nature of the atmosphere.
Met Office long-range forecasts are updated daily and give a broader indication of how the weather might change or differ from what is normal at the time of year across the whole of the UK.
A Met Office blog on the issue adds: “Forecasting impactful snow is famously tricky in the UK. There are a number of factors that our expert meteorologists look for and numerous competing elements that all have to be exact for snow to actually fall.
“Sometimes, just a fraction of a degree in temperature can make the difference between the chance to build a beautifully formed snowman, and the joys of a sleety slushy day. That’s why forecasting snow weeks in advance is extremely tricky.
A more accurate prediction is made once in five days or less. In the case of Christmas Day, this means a proper, more localised forecast can be expected on 20 December.
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