Scotland is preparing for severe winds, with gusts of up to 90mph being forecast.
The Scottish Government said schools across west, central and southern Scotland would either not open or close early.
The government's Resilience Committee was told key routes were likely to be closed and motorists would be advised not to travel.
Very severe gales are expected to affect the extreme west from 0700 GMT.
The strongest winds are expected from 1200 GMT in Glasgow and west-central areas and 1500 GMT in the east of the central belt, lasting through into the evening.
The Met Office said there was significant risk of structural damage.
The government said the level of travel warning was "unprecedented for high wind situations".
By travelling motorists may be putting themselves at serious risk, such is the severity of the forecast conditions”
End Quote Assistant Chief Constable Allan Moffatt
Following a meeting of the Scottish cabinet on Wednesday evening, local authorities were advised that all schools in the west of the central belt should be closed on Thursday, with schools in the east closed from lunchtime.
It had earlier been confirmed that schools would close from lunchtime in the Borders, Renfrewshire and Stirling Council areas.
Scotrail has advised commuters to consider leaving work early because of the possibility of afternoon rush-hour disruption.
Deputy First Minister Nicola Sturgeon said: "The very latest information from the Met Office's Chief Forecaster which we received tonight shows that we can expect very severe gales, at wind speeds not seen for many years, across large parts of western, central and southern Scotland throughout Thursday.
"On the basis of the earlier 'Red Warning' from the Met Office, some Councils had already taken the precaution of closing schools early to make sure that parents can safely collect children before the most dangerous weather and travel conditions arrive.
"In light of tonight's latest forecast, and in particular the timings which suggest the severe weather affecting the west-central part of the country earlier than originally anticipated, some of these closure timings may have to change."
Parents have been advised to check their local council websites for information on school closures.
Assistant Chief Constable Allan Moffatt, from the Association of Chief Police Officers (Scotland), said it was likely that some or all of the major bridges would be closed.
He said: "This will inevitably cause disruption on major routes and have an impact on other road networks.
"The predicted impact of the wind is such that it may cause structural damage and is a specific danger to high sided road vehicles."
He added: "By travelling motorists may be putting themselves at serious risk, such is the severity of the forecast conditions."
Network Rail is expected to apply a speed restriction of 50mph from 10:00 GMT on Thursday because of the danger of fallen trees and other debris on lines.
Its route managing director for Scotland, David Simpson, said: "We will have over 350 engineers out on the network, working to keep the railway running.
"However, the extreme nature of the conditions, and the impact they can have on our infrastructure, means that a speed restriction is necessary in the interests of safety."
Scotrail has prepared a temporary timetable, with a reduced service likely from mid-morning.
Police in the Highlands have warned drivers to prepare thoroughly for any journeys they have to make.
Insp Steve Mardon said: "Be prepared for the worst by taking blankets, extra clothing, a shovel, food and drinks, and making sure your mobile phone is fully charged and you have useful contact numbers."
Tayside Police said fresh falls of snow and blizzard conditions were expected in places.
Another casualty of the weather is the Christmas display in Glasgow's George Square. Glasgow Life has said the festive attractions will be closed all day on Thursday as a precaution.
Extremely difficult conditions are forecast around Scotland's coasts. The Met Office is warning of south or southeast winds of force 6 to gale force 8, veering into the west or southwest and increasing severe gale 9 to violent storm 11.