"During Friday, increasingly frequent snow showers already affecting parts of Scotland, Northern Ireland and northern England will extend across many other northern and western parts of the United Kingdom", said the Met Office.
A spokesperson for The Weather Channel said: "Storm Caroline will become situated to the north-east of Scotland".
Transport networks face widespread disruption and power cuts are possible as a result of the extreme weather, the forecaster said.
Amid gusts of up to 90mph, flying debris is likely and could lead to injuries or danger to life, according to the Met Office.
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Some roads and railways likely to be affected with longer journey times by road, bus and for train services.
People travelling by road, rail, air and ferry have been warned of potential delays and service cancellations.
Met Office meteorologist Marco Petagna said: 'Wednesday will see the last of the mild days, with temperatures in double figures, between 10 and 12 degrees (50F-54F).
Winds are forecast to strengthen across parts of Britain on Wednesday ahead of the arrival of Storm Caroline.
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A yellow "be aware" weather warning is in place for the region, which runs from 8am on Thursday until just before midnight.
All schools and nurseries in Lewis, Harris and Uist in the Western Isles are closed to pupils on Thursday as a precaution while 31 primary schools, five secondary schools and 19 nurseries in the Highland Council area and two schools in Aberdeenshire are shut. "More broadly across Scotland there will be 60-70mph gusts, but in exposed areas we could see 90mph".
Some flights in the western isles have been cancelled.
Flood alerts are also in place for northern parts of Scotland, with strong tidal surges and heavy showers predicted by the Scottish Environment Protection Agency.
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