National Highways has issued a severe weather alert for snow in the south of England for tomorrow and Thursday – asking people to reconsider journeys on parts of its road network.

The weather warning means driving conditions will be extremely difficult, especially for larger vehicles and those not equipped with four wheel drive between midday tomorrow and 3am on Thursday, in the south east and the south west.

National Highways is asking everyone travelling in these areas to consider if their journey is essential.

HGV drivers are asked to avoid parts of the road network with steeper than normal inclines. This could potentially lead to their vehicle becoming jack knifed or stranded in the wintry weather.

Where vehicles get stuck it can prevent gritting vehicles getting through to treat the road with salt or to plough snow clear from the road.

National Highways executive director of operations Duncan Smith said: "We are well prepared and our gritters have been out in full force since Friday and will continue to treat the roads. We are asking drivers to plan ahead, check the forecast and allow more time for their journeys.”

Drivers are advised to take extra care in these areas which are expected to be the most impacted by the severe weather:

South East

  • M4
  • M25
  • M3
  • A303
  • M20
  • M23
  • A3
  • M40 junctions 1 to 9

South West

  • A38 Haldon hill
  • A303
  • A30 Okehampton
  • M5 junctions 31 to 22
  • A417 near Gloucester
  • M4

Snow is expected in the morning, followed by a more significant second wave of snow in the afternoon and evening.

It could be prolonged and occasionally heavy, particularly during the evening rush and to the east of the M5, leading to potential slow traffic and loss of traction on steep inclines. The current estimate is for 2 to 5cm of snow, and up to 10cm on higher ground and hills.

There could then be icy stretches during the morning travel period on Thursday, presenting another hazard to motorists.

National Highways, in conjunction with the Met Office, are strongly advising that travel in these areas is likely to be extended or even disrupted. Road users should heed messages on the overhead signs and listen for radio updates. Further information can be found by visiting or calling the National Highways Customer Contact Centre on 0300 123 5000.