Advertisement

How far in advance snow can be accurately forecast, according to the Met Office

Predicting snow in the UK can be difficult. (PA)
Predicting snow in the UK can be difficult. (PA)

Forecasts of incoming snowstorms are fairly frequent at this time of year - but it can be difficult to figure out which are accurate and which are closer to being speculation.

The problem is that snow is much harder to predict in the UK than other types of weather like rain or wind. This difficulty means accurate forecasts can normally only range a few days into the future rather than a week or more.

Given the severe disruption blizzards can cause (or the joy that building a snowman can bring), there is often an understandable surge in interest when any long-range forecast of heavy snowfall is made, regardless of accuracy.

Met Office spokesperson Stephen Dixon told Yahoo News UK: "Sometimes you can see media articles which say 'maps suggest snow' and I think the important thing to underline is that a single map from a single model run for weeks isn't a good indicator of a fully-fledged forecast."

Snow needs multiple conditions to line up in order to fall in the UK. (PA)
Snow needs multiple conditions to line up in order to fall in the UK. (PA)

He said Met Office forecasts are informed by "hundreds of model runs" with meteorologists then analysing them and making the final forecast. Dixon added: "One-off model runs for weeks away aren't a good indicator of impending snow. It is much more reliable to check in with meteorological organisations which can explain some of those uncertainties."

Recommended reading

How is snow forecast in the UK?

Forecasting snow in the UK is quite complex in comparison to other countries on the same latitude.

"The reason for that is there competing factors that indicate a snow forecast," according to Dixon. He said the key things to look for are "where the air has come from" with weather patterns hitting the UK from all directions.

By looking at where the air has come from, forecasters predict when strong winds, rain or sun are likely by predicting the pressure that will develop in those areas. Many other types of weather patterns only need one condition to develop but snow needs a lot of factors to line up making it "quite hard to predict" anything beyond three to four days in the future.

Snow can cause heavy disruption up and down the UK. (PA)
Snow can cause heavy disruption up and down the UK. (PA)

For snow to happen in the UK, warm air needs to meet cold air, there must be heavy precipitation, and the temperature needs to be between 0-3C. Most weather forecasts more than five days in the future have some amount of range in them which means it is extremely hard to predict if all of the factors required for snow will definitely line up.

Dixon added that because the UK is an island nation, the waters around the country can also impact the likelihood of snow.

Forecasting where the snow is going to land is also not a simple job, with temperatures varying depending on how high up the location is. The top of a hill, for example, may be a few centigrade cooler and tip it into the ideal freezing range while the surrounding area may still be too warm.

Asked how meteorologists determine if the snow is going to be a light coating or a serious blizzard, Dixon said: "You need to be set up in a meteorological situation where snow is possible and then you can work out from there where exactly and how much snow will fall, but it is one of the trickier weather types to forecast."

Is there any snow forecast in the UK?

Over the next few days, there is only expected to be snow in the Scottish Highlands, which is usual for this time of year. Smatterings of snow and hail, combined with a lot of rain, are forecast throughout the weekend and Monday in northern Scotland.

The rest of the country will remain dry for the weekend with some rain coming over northern England on Monday.