Met office
UK Outlook for Friday 18 Jan 2019 to Sunday 27 Jan 2019:
It will be mostly settled for a time on Friday, especially in the east, before thickening cloud and outbreaks of rain, perhaps with some hill snow, try to move eastwards later, with strong winds. The rain and hill snow will make further eastward progress on Saturday, perhaps with northeastern areas staying dry. Thereafter, it looks set to remain mainly cold, unsettled and sometimes windy, with gales possible in the north. Any milder spells will tend to be brief, and associated with longer spells of rain. The rain could turn to snow almost anywhere, but particularly across northern and central areas, especially later in this period. Some drier, brighter spells are likely, perhaps with snow showers, especially in the east. During such spells, frost could become widespread and severe.
UK Outlook for Monday 28 Jan 2019 to Monday 11 Feb 2019:
For the end of January and into early February, there is an increased likelihood of cold weather being established across all of the UK, with temperatures continuing a downward trend to become cold or very cold. This would bring a greater risk of snow, ice and widespread frost, particularly across northern parts of the country. However, there remains uncertainty over the extent of the cold weather and how long it will last, and it is still possible that some milder and wetter interludes will intersperse this generally cold period, especially in the south.
https://www.metoffice.gov.uk/public/weather/forecast