Staying cold with more snow in places during the remainder of the week

Cold air is in place across the UK this week, thanks to low pressure over southern Norway and high pressure to the northwest continuing to pull down cold arctic air from the north. So it’s a cold start this morning, with temperatures widely below freezing at dawn, with a widespread frost, temperature as low as -7C in Cumbria. 

Northern Scotland and the north coast of N. Ireland will continue to see wintry showers through the day, falling as snow inland with further accumulations across northern Scotland. Further accumulations of 2 to 5 cm are likely in places, with up to 5 to 10 cm above 200 metres. A Met Office yellow warning is in force until 12 noon today. The warning has a medium likelihood and low impact on their ‘impact matrix’. 

At the other end of the UK, we’re watching the precipitation on the northern flank of an area of low pressure forecast to track east off the Atlantic across NW France later today. Outbreaks of rain, sleet and snow are expected to spread east across southern counties of England through the afternoon and evening, mostly south of the M4 and the Thames through London. 

There is some uncertainty over intensity of precipitation and temperatures at the surface, which will dictate whether rain or snow falls at lower elevations, higher ground and away from the coast more favoured for snow to fall. Accumulations of snow don’t look to be much by the end of the today, with precipitation forecast to weaken as it moves east then pulls away east from SE England later this evening. Perhaps 1-3cm over higher ground, a dusting at lower elevations inland, though perhaps locally more if precipitation is heavier than most models predict. Dartmoor could see up to 10cm, with precipitation likely to be heaviest towards SW England before weakening as it spreads east. Not expecting any major disruption, with accumulations generally light. A Met Office yellow warning for snow is in force across southern England until midnight tonight. The warning has a very low likelihood and a medium impact on their ‘impact matrix’.

A hard overnight frost tonight is looking likely away from the far southeast, especially where there’s snow on the ground, with temperatures falling to between -3C and -10C widely, but over snowfields it could be as cold as -14C to -16C in prone sheltered rural locations. In northern England and Scotland we may see a few spots fall lower than this, perhaps as low as -20C. 

Thursday is looking dry, sunny and cold after a frosty start - away from northern Scotland - where further sleet and snow showers are likely spreading down from the north. Another very cold night to follow, with a widespread hard frost, some very low temperatures over the snow fields.

Friday likely to see the last snow threat of this cold spell away from northern Scotland. An elongating occluding frontal system, aligned northwest-southeast, looks to move in from the west off the Atlantic across Ireland, SW England and Wales Friday morning, rain along the fronts turning to snow inland across Wales and over higher ground in SW England. However, there is a great deal of uncertainty over how far east the front and its rain, sleet and snow will get. This is because the frontal system will bump into a ridge of high pressure lying over the UK, with models often struggling on how quickly to weaken fronts in such set-ups. Most models don’t get precipitation any further east than Midlands and central southern England on Friday, with it fizzling out past here. But this may change, so we will keep you updated. Accumulations of any snow inland across Wales and the southwest uncertain at this stage, but the risk of disruption looks low for now. But, again, this could change.

Friday’s system across the southwest weakens into early Saturday, then high pressure looks to build in over the weekend, with most areas becoming dry but remaining cold, with a risk of widespread overnight frost.