Heavy snow and 90mph winds are set to hit Scotland as Storm Caroline sweeps in.
The Arctic weather is likely to cause delays for travellers between Thursday and Saturday with ScotRail announcing the cancellation of services in the north of the country. Ferry services are also at risk.
The Met Office has issued warnings for wind, snow and ice covering most of Scotland ahead of the storm's arrival.
They include a wind amber warning - the second most serious category - for the Highlands and Islands on Thursday.
STV weather presenter Sean Batty said on Wednesday: "Caroline will start drifting to the north west of Scotland tonight and into tomorrow morning.
"The storm is expected to bring winds of 60mph to 70mph widely across the north, with a risk of gusts reaching 80mph in the most exposed areas.
"Strong winds may coincide with high tides, potentially producing some large waves and causing coastal flooding."
The Western and Northern Isles are likely to be worst hit by the wind but severe gales may also hit the central belt on Thursday, Sean warned.
"The strong winds will also lead to blizzard conditions in the north of the country," he said.
"Frequent heavy snow showers will come in on the Arctic air flow, widely bringing several centimetres of snow to the north and the Hebrides, with up to 20cm possible on higher ground.
"The colder air is expected to last through next week with a risk of further snowfall in places."
Despite the chilly conditions, Sean said it is still too early to predict a white Christmas.
He added: "The favoured position at the moment is that generally colder conditions will last until the end of the month and further snowfall can be expected."
Ferry operator CalMac has advised travellers to expect severe disruption and cancellations on Thursday.
The company is urging urge passengers who need to travel to allow extra time for their journey and to keep track of the status of their sailing on the firm's website before setting out.
Meanwhile, ScotRail said it will suspend services from Aberdeen to Inverness, Inverness to Wick, Inverness to Kyle of Lochalsh and Glasgow Queen Street to Oban/Fort William/Mallaig.
A safety inspection will be carried out on these routes on Thursday morning, when a further decision will be taken about when to resume services.
Speed restrictions will also be in place for services between Perth-Aberdeen and Perth-Inverness due to expected winds of up to 60mph. This means trains will be slower and services will be disrupted.
Production has also been shut down on a North Sea platform after safety fears forced all workers to be removed.
A total of 69 of the 159 staff on Ninian South, about 240 miles from Aberdeen, were taken off the structure as a precaution on Tuesday.
However, with forecasters raising their weather warning to amber, operators CNR decided to fully downman the platform.
Scottish and Southern Electricity Networks (SSEN) said it has deployed 850 engineers and support staff to areas expected to take the brunt of the storm.
Catering and welfare vans have also been sent out by the company to offer support to customers who experience a loss of supply.
Dale Cargill, director of customer operations, said: "Our established resilience plans are in place, with additional frontline teams, support staff, equipment and welfare facilities being mobilised in the areas expected to be impacted.
"I would like to reassure our customers that we are well prepared and resourced to respond promptly to any damage to our network, where it is safe to do so.
"If any of our customers do experience a power cut, or have any concerns about a vulnerable family member or community member, I would encourage them to please call us on the national power cut emergency number 105."