UK weather: Storm Abigail brings huge waves and 90mph winds
Northern Ireland is predicted to escape the worst but temperatures are expected to drop with strong winds, heavy rain and wintry conditions on higher ground.
Storm Abigail is arriving in the UK bringing gusts of up to 90mph.
Parts of the north and west coast of Ireland are being hit with heavy rain and strong winds but the biggest impact will be in Scotland.
The Met Office has amber "be prepared" warnings in place for rain and wind in the north west of Scotland, while yellow "be aware" warnings cover much of the rest of Scotland.
All schools in Shetland and the Western Isles will be closed to pupils on Friday.
A number of CalMac ferry sailings have already been cancelled and commuters on the trains and roads are facing disruption.
Western Isles Council said every school and nursery in its area will be closed to pupils on Friday. Schools will be open for teaching staff from 10am.
Shetland Islands Council also announced that its schools will be shut to pupils due to the forecast of strong winds and the possibility of lightning strikes.
Orkney Islands Council said any decision on school closures would be taken on Friday morning.
The closures come amid Met Office warnings of likely gusts of 70-80mph, potentially reaching up to 90mph across exposed locations in the north west of Scotland.
The storm, which is expected to reach its height overnight, has already brought strengthening winds and heavy rain to many parts of Scotland.
By 5pm, CalMac said 24 of its 26 ferry routes were disrupted.
The firm has urged travellers to "think carefully" if they are planning to visit the west coast.
Train operator ScotRail said there is minor disruption on its routes from Glasgow to Carlisle/Newcastle, Glasgow to Ardrossan/Ayr/Largs and Kilmarnock to Ayr.
The Forth Road Bridge has been closed to high-sided vehicles, cars with trailers, caravans, motorcycles, bicycles and pedestrians.
High wind warnings are in place for key crossings, including the Erskine and Kessock bridges, while warnings of surface water have been issued for key commuter routes the M90 and M74.
Dublin Airport said it is experiencing some minor disruption to flight schedules due to strong winds.
Meanwhile, Dumfries and Galloway Police said there are a number of trees down across the region. Traffic Scotland said a fallen tree on the A82 is partially blocking the road and affecting traffic in both directions.
And the Scottish Environment Protection Agency (Sepa) has flood alerts and warnings in place for Dumfries and Galloway, Argyll and Bute, Ayrshire and Arran, Skye and Lochaber, and Speyside.
Met Office meteorologist Emma Sharples said: "The main centre of the low pressure system around which all the winds are going to be strongest is moving from the Atlantic towards the north west parts of Scotland at the moment. That's going to continue to edge towards us.
"There's obviously rain already setting in and winds strengthening across the country and that will continue to be the case through the rest of this evening, with the band of rain spreading eastwards across Scotland and then the wind turning from a south westerly to more of a westerly as we go through towards midnight."
Ms Sharples said the Western Isles had already seen gusts of 55mph and upwards by mid-afternoon.
Members of the public have been asked to secure any lose debris, while builders have been advised to secure scaffolding and any lose items on building sites.
People are also being asked to look out for elderly and vulnerable people.
The Scottish Fire and Rescue Service (SFRS) has urged people to take extra care if they are using candles during any power cuts.
Scottish Hydro Electric Power Distribution said it has moved to "yellow alert" and had more than 500 engineers in place in advance of the storm hitting.
The Met Office amber alert - which affects the Outer Hebrides, Highlands and Orkney and Shetland, warns: "South-westerly severe gales will develop later on Thursday, increasing storm force for a time as they veer westerly overnight into Friday morning. Gusts of 70 to 80mph are likely, and perhaps 90mph across exposed locations.
"Winds will begin to decrease across the Western Isles and the mainland on Friday morning. The strongest winds over the Northern Isles will occur on Friday morning before becoming less strong on Friday afternoon."
The storm is the first such weather system affecting the country to merit a name as part of the Met Office ''name our storms'' project, which asked the public to suggest names.
Officials hope the project will help raise awareness of severe weather and ensure greater safety of the public.
While Northern Ireland is predicted to escape the worst, temperatures are expected to drop with strong winds, heavy rain and wintry conditions on higher ground.
Saturday is expected to begin bright before the wind and rain again take hold.
November has, so far, been milder than usual, with temperatures far exceeding the average for this time of year.
Yesterday, a temperature of 16.1C was recorded at Murlough, Co Down, making it the warmest November night since records began.
A Met Office spokesman said a mild air being pushed up from the tropics has been responsible for the unseasonable conditions.
He added: "We have had very mild south-westerly air flowing over the UK which is drawn up from over the tropics.
"On the other side of the Atlantic the jet stream is turning southwards and so what goes down most come up as warm air is being pushed north.
"We have had a few weeks now where we have enjoyed winds coming from that direction."
Naming a storm
The Met Office, as part of a project with the Irish service, Met Eireann, has begun naming the storms expected in the UK and Ireland.
It's hoped a single system will help communicate weather warnings better to the public.
The public was asked to contribute to the project by providing the names.
After Abigail, the next storm will be named Barney.