I disagree a little - is say that the 13th Dec forecast for the first half of Jan is pretty accurate especially when you factor in the 4 week time lag from when they made it. We are having a colder than average period, with frost and fog and then through next week there is likely to be snow for some. That's pretty much how they described the first half of Jan up to the 11th - is say hats off to them.

BBC monthly outlook

Summary

Becoming more unsettled, then turning colder

Saturday 5 January—Sunday 13 January

Windy for a time but otherwise relatively settled

High pressure has been the dominant feature of our weather for a while now, and it looks likely to remain fairly significant this weekend and to a certain extent, next week too.
Saturday will be dry across most parts of the country although a cold front will move in from the Atlantic on Saturday afternoon, bringing outbreaks of rain to Scotland and Northern Ireland in the evening, then northern England and Wales overnight. This front is not a particularly active feature though and it will become weaker over time, so the rain it brings will not be particularly heavy and it will become increasingly patchy. Sunday may see a little rain across the north of the UK, most likely over northern England, but the south should remain dry. Much of Scotland will be dry with sunny spells.

After a chilly start to the weekend, temperatures should be a little nearer to normal by Sunday. The new week is likely to start on a more unsettled note as a deep low pressure system passes the north of the UK. This system will bring a spell of windy weather to many areas, and a risk of gales for Scotland. There will also be showers and more widespread rain too. By Tuesday, the low pressure system will be to our east and, with high pressure to the west, we will have a spell of cool northwesterly or even northerly winds. Some wintry showers are also possible. The second half of the week should see high pressure building back towards the UK although perhaps not becoming the dominant feature that it has been. There will be a chance of unsettled weather affecting the country, perhaps most likely next weekend, but many areas will have a relatively dry and calm end to the week.

Monday 14 January—Sunday 20 January

Wetter, windier and cooler

We'll see the ridge of high pressure shifting southwards and westwards away from the UK. This will allow northwesterly winds to affect the country, pushing cooler air across most regions. It will probably be wetter than the coming week, particularly across the northwest of the UK and there will be a chance of some spells of windy weather too. We are likely to see a cooling trend with regard to temperatures and it could become rather chilly by the end of the week. This would mean that there will be a greater chance of wintry showers across northern parts of the country than we have seen for much of the winter so far.

As ever, there is a little uncertainty in the forecast at this range. The main alternative to our expected forecast is that high pressure will 'rebuild' across the south of the UK. This would tend to limit the amount of northwesterly winds we see, so in this scenario it would be less cold, and probably less wet and windy too. There would still be the chance of occasional spells of wetter and windier weather too.

Monday 21 January—Sunday 3 February

Probably, but not definitely, becoming colder

In our last outlook, we mentioned the possibility of it becoming colder during the middle or end of January, due to developments in the upper atmosphere over the North Pole. There has been a dramatic rise in the temperature of the Arctic stratosphere. Meteorologists call this kind of event a Sudden Stratospheric Warming or SSW. They happen several times per decade and are part of the natural variability of the global climate system. The SSW event that has just occurred has disrupted the winds which make up the polar vortex, and it looks as though this disruption could continue for several weeks.

This, combined with other global weather patterns, means that the UK has an increased threat of significantly colder weather developing as we head through the final third of January and into February. Our longer-range forecast data certainly shows a trend towards colder weather across northern Europe, including the UK, at the end of this month and well into the start of February. There are also indications of an increased risk of snow for the UK. However, there is still some uncertainty over the extent to which the cold weather will affect us. In fact, there is even a 25% chance that we could continue to be affected by Atlantic weather systems, with any cold air tending to be confined to other parts of Europe.

https://www.bbc.co.uk/weather/outlook

Decent cold update 

UK Outlook for Thursday 10 Jan 2019 to Saturday 19 Jan 2019:

Most areas will be dry on Thursday with some sunshine after an early frost. However, the far southeast will have rain showers and some rain will affect the northwest. On Friday cloud will extend to most parts from the northwest, accompanied by a rise in temperature. However, it will remain mostly dry, perhaps with heavier rain reaching the northwest later, where winds may also strengthen. Over the weekend and into the following week, the weather is set to become generally more changeable, with gales at times and bands of rain crossing from the west. Some snow is expected in the north, especially in brighter, showery, colder interludes between weather systems. The south and southeast can expect the best of any drier and brighter periods. Meanwhile, some frost is still likely.

UK Outlook for Sunday 20 Jan 2019 to Sunday 3 Feb 2019:

The period may start with predominantly wet and windy weather, and a chance of heavy rain and gales at times, especially in the north. Hill snow is also possible, as well as snow to lower levels at times in the north. In the south though, there could be some drier and brighter periods too. Temperatures will vary between mild and rather cold at times, with overnight frosts during settled spells. However, as the period progresses there is an increased likelihood of a change to much colder weather becoming established generally, bringing an enhanced risk of frost, fog and snow. These notably colder conditions are by no means certain though, and in any case, some milder, wet and windy interludes are still possible.

https://www.metoffice.gov.uk/public/weather/forecast 

It actually says in that release "There is a 60% probability of severe cold weather"  To me, it is bog standard winter anticyclonic conditions. 

What is their definition of severe cold?  

They are issued by the Met Office when one of the following happens:

• The mean temperature falls below 2°C for 48 hours or longer.
• There's heavy snow and/or widespread ice.

Pathetic 

what a load of tripe. Talk about snowflake Britain....

UK Outlook for Friday 11 Jan 2019 to Sunday 20 Jan 2019:

Friday will be cloudy for many, with the best of the brightness in the north. It will probably turn more unsettled from the northwest into Saturday, with heavy rain and strong winds followed by showers, and some snow is likely over higher ground in the north. Gales will be possible in the north and west, and it will turn colder from the northwest. The weather is set to become generally more changeable, with gales at times and bands of rain crossing from the west. Some snow is expected in the north, especially in brighter, showery, colder interludes between weather systems. The south and southeast can expect the best of any drier and brighter periods. Meanwhile, some overnight frost is still likely in clearer spells.

UK Outlook for Monday 21 Jan 2019 to Monday 4 Feb 2019:

This period is likely to start with predominantly wet and windy weather, and a chance of heavy rain and gales at times, especially in the north. Hill snow is also possible, as well as snow to lower levels at times in the north. In the south though, there could be some drier and brighter periods too, especially in the southeast. Temperatures will vary between mild and rather cold at times, with overnight frosts during settled spells. However, as the period progresses there is an increased likelihood of a change to colder weather becoming established generally, bringing an enhanced risk of frost, fog and snow. These notably colder conditions are by no means certain though, and in any case, some milder, wet and windy interludes are still possible.

https://www.metoffice.gov.uk/public/weather/forecast 

Heavy snow in Germany, Austria, Greece causes chaos for travellers

"Heavy snowfalls across Europe — even in Greece — have thrown travel plans into chaos, trapping hundreds in alpine regions and airports, and leaving snow on Italian beaches.

Heavy snow caused travel chaos in parts of Germany and Austria as authorities closed roads and train routes because of avalanche danger and airports reported weather-related cancellations on Saturday. Munich Airport, Germany’s second biggest, said 120 flights were cancelled and others were delayed while workers cleared runways of snow and removed ice from planes"

https://www.news.com.au/travel/travel-updates/incidents/heavy-snow-in-germany-austria-greece-causes-chaos-for-travellers/news-story/0aa605686ccf93c27db642b9933806c4

While wait for the SSW effects I’m sure this weather will be attributed to the SSW. 

This is my fear is that Greece getting so much cold and snow for over a week and more to come for Austria etc ...I do wonder if this is the effect of the SSW and this block right now over the UK is responsible. This it's going Pete Tong for us.. 

Despite so many models including CFSv2 and our fee own met office glosea 5 went for a milder than average January for many parts of southern and eastern Europe...!

UK Outlook for Saturday 12 Jan 2019 to Monday 21 Jan 2019:

It will probably turn more unsettled in the north during the weekend, with heavy rain and strong winds, followed by showers, these possibly turning wintry over higher ground. Elsewhere, mostly cloudy with perhaps some brighter spells to the lee of high ground. Windier for many, with the risk of coastal gales in the north. There is a trend towards more changeable conditions during next week, with spells of rain followed by colder and showery conditions, possibly turning to snow on northern hills. The best of any drier and brighter interludes will be towards the south. Windy for many, with gales possible in the north. Temperatures overall near to above average, although some colder interludes are possible, especially in the north. Overnight frosts are still likely in any clearer spells elsewhere.

UK Outlook for Tuesday 22 Jan 2019 to Tuesday 5 Feb 2019:

Changeable conditions are favoured at the start of this period, with spells of rain and strong winds, with some hill snow in the north at times. The driest and brightest conditions are likely to be in the south and southeast. Temperatures overall are likely to be near or falling below average. Any milder interludes probably becoming short lived, although the greatest chance of colder weather is likely to be in the north. As the rest of the month progresses and into early February there is an increased likelihood of colder weather to become established generally, which will bring an enhanced risk of frost, fog and snow. These notably colder conditions are by no means certain though, and in any case, some milder, wet and windy interludes are still possible.

https://www.metoffice.gov.uk/public/weather/forecast