Southern Scotland and northern England are expected to be hit with 2-5cm of snow on Friday, which could affect road and rail journeys.
The yellow - “be aware” - severe weather alert from the Met Office will be in force from 3am to noon.
A spokesperson for the agency said: “A spell of snow is likely across parts of northern England and southern Scotland on Friday morning.
“Some roads and railways are likely to be affected, with longer journey times by road, bus and train services.
“Some delays to air travel are also possible.”
The Met Office said snow would affect ground above 100m, which includes part of most cross-Border routes.
It also said up to 10cm was possible over higher ground.
An ice alert has been issued for tonight - the third night running - which covers the north and extreme west of Scotland until noon tomorrow.
The Met Office spokesperson warned: “Icy patches are expected to develop on untreated surfaces, pavements and cycle paths and where showers wash off treatment.
“Some injuries from slips and falls on icy surfaces may occur.”
“1-2cm of snow may accumulate above about 100m, with perhaps 5cm or more locally over the higher ground of north Highland.
“Temporary deposits may also occur at lower levels, mainly late in the night.”
The warnings came after iced-up rail points at Rutherglen, near Glasgow, caused significant train disruption today.
The problem, reported at 8am, caused delays to services across the Central Belt until 3:30pm.
A separate signalling problems in Edinburgh, caused by a mechanical fault, prevented any ScotRail trains from moving in the capital around 8am.
ScotRail tweeted at 8:16am: “No services are able to run in or out of Edinburgh.”
When trains resumed, their frequency was reduced on several lines, including services being halved on the main Edinburgh-Glasgow route.
ScotRail said the disruption was expected to continue until 5:30pm.
Bad weather delayed CalMac ferry sailings between Ullapool and Stornoway, and NorthLink warned of possible disruption to Orkney and Shetland.
In England, heavy snow and ice disrupted airports and motorways in England and left thousands without power.
Passengers at Stansted Airport were delayed while the runway was closed temporarily to allow safety checks to be carried out.
Travellers at Luton Airport were warned of possible delays due to sleet and snow, with reported hold-ups of over two hours while crews de-iced their plane.
A lorry crash on the M1 closed all three southbound lanes and left traffic backed up in its wake, with a string of weather-related crashes elsewhere.
The RAC said it saw a 15-20 per cent increase in call-outs compared with this time last year, including 12 relating to a pothole causing significant damage to vehicles on a section of the M25 around London.
Highways England also reported “severe conditions” in both directions on the A14 near Kettering, with motorists asked to avoid the area while all available resources were deployed to help move vehicles, some of which had been stuck for several hours, and clear snow from the carriageway.
Another HGV jack-knifed in heavy snow on the M5 in Gloucestershire, as heavy snowfall overnight into Wednesday affected western parts of central England.
Western Power Distribution and Scottish and Southern Electricity Networks said more than 13,000 homes remained without power, most in the West Midlands, along with others in the East Midlands, south west of England, and Wales.