Winter is coming and there will be some snow

After the warmest December on record for the UK, with temperatures more akin to spring, winter is finally coming next week.

In December, mean temperatures – an average of day and night temperatures – were 4.1C above normal, giving overall warmth that was more typical of April or May.

It was the most anomalously warm month ever recorded for the UK and has sent nature into a spiral of confusion, with plants blooming like winter hasn’t happened.

However, there’ll be a big shock to the system for all of us next week, as winter is finally going to arrive across the country.

Why the change to wintry weather?

Into next week, the jet stream will split in two over the middle of the Atlantic Ocean – something that is known as bifurcation in the meteorological world.

One branch of the jet stream will be active and well south of the UK, heading into southern France, Iberia and the Mediterranean, with a separate weaker branch heading north towards Greenland.

This will herald a big change from the single powerful jet stream that has been storming across the Atlantic in the last month, travelling at speeds of up to 230mph, 30,000ft in the atmosphere.

As a result, storms bringing wet, windy and mild weather will be steered away from us, allowing high pressure to build to the west of the UK and low pressure to sit to the east.

This particular orientation of high and low pressure means that a north to north westerly wind will set in, allowing cold Arctic air to flood southwards.

How cold will it get?

The change to colder weather will be gradual, with temperatures initially returning to average this weekend and early next week.

However, from Wednesday onwards, there’ll be another step change to something even colder, with temperatures below average.

During the daytime later next week, temperatures will struggle to get much above 0-3C in the north of the UK, with 3-6C likely in the south.

At night, there will be widespread frosts, with temperatures widely falling to freezing or a few degrees below, with temperatures over any snow cover falling even lower – possibly down to -10C.

Will there be snow?

Snow is notoriously difficult to forecast far ahead in the UK, because temperatures are often borderline for it to fall and settle in any great amounts – unless you live in the north or high up on a hill.

Nevertheless, given the weather set up next week, it is possible to get an idea of where snow is most likely, given the direction of the wind.

At the moment, it looks like northern, eastern and western coast areas of the UK, up to around 10-20 miles inland, will be most likely to see any falling snow, with accumulating snow in greatest amounts over the hills and mountains.

However, sometimes, there can be more active features called troughs, which drift down in the northerly wind.

These troughs enhance snow shower activity and can give snow over a wider area – even well inland, but it’s virtually impossible to predict these with any useful confidence so far ahead.

Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton

Graphics: Wetterzentrale and Tropical Tidbits