Storm Agnes - the first named storm of the meteorological year - has hit the UK.
It is expected to bring strong winds and heavy rain which could result in widespread disruption.
The Met Office and Met Éireann have warned of potential travel chaos as the storm hits.
The storm could also see an increased risk of flooding in certain areas.
WATCH NOW: Storm Agnes forecast
The seasonal storm is also set to bring with it roughly 2.4 inches of rain in parts of the country.
Meanwhile, a yellow weather warning for wind has been issued by the Met Office, covering large parts of the UK, including Manchester, Cardiff, and Belfast.
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FINAL UPDATE TONIGHT
Wet and windy weather has already spread across Ireland and Northern Ireland into western parts of Britain.
The rain will be heaviest and most persistent over parts of Scotland, Ireland and Northern Ireland.
Weather warnings remain in place until 7am on Thursday, September 28.
20:30pm UPDATE: More than 500 properties in north Cornwall lose power
National Grid say 530 properties have been affected in the Jacobstow area along with 50 around Westward Ho! in north Devon.
The strongest gusts have been 63mph (101km/h) on the Isles of Scilly and 49mph (79km/h) in Newquay.
Coastguards are warning people to "take weather warnings seriously and stay safe".
19.10pm UPDATE: 'Dangerous building incidents' and flooding in Cork
Cork City Council/ Twitter
Cork City Fire Brigade say they have been called to "dangerous building incidents" across the area.
A statement said flooding and several downed trees have also been dealt with this afternoon during a "busy shift".
Orange wind warnings have been extended for another two hours until 7pm in the country.
18:00pm UPDATE: 1,500 homes without power
NI Electricity has warned that power cuts are possible, and ESB networks are showing power faults in a number of counties including Cork, Wexford and Tipperary.
A total of 1,500 homes are currently without power in Co Armagh.
Winds of up to 80mph are expected to hit parts of Ireland later today as weather warnings remain in place.
17:30pm UPDATE: Roof blown off building
The scene in Youghal, Co Cork, where a roof has been blown from a building
Damaging winds and big stormy seas have caused disruption in Youghal, Co Cork with one roof being ripped off a building.
Agnes, the first named storm of the season, will affect western regions of the UK and Ireland, with the most powerful winds expected on the Irish Sea coasts.
A yellow alert for rain is in force until 8pm, while a wind alert will remain in place until 7am on Thursday.
17:00pm UPDATE: Flight and ferry travel disruption
Flights have struggled to land at Belfast airport due to Storm Agnes
Flights to and from Belfast airport have been cancelled as Storm Agnes rages on.
A spokesperson for Belfast City Airport has said: "Disruption to schedules across the UK due to the weather is likely.
"Passengers are advised to check the status of their flights with their airline before travelling to the airport. Flight information can also be viewed at belfastcityairport.com"
All of Wednesday's daytime passenger ferry sailings to and from the Isle of Man have been cancelled due to expected gales across the Irish Sea.
15:50pm UPDATE: Storm Agnes is set to cause chaos until 7am on Thursday
Storm Agnes will batter parts of the UK until 7am on Thursday morning.
The warning area has been extended further east and north, now covering Perth, Dundee and Aberdeen.
Strong winds and heavy rainfall has arrived from the south this afternoon bringing 30-50 mm of rain, perhaps 60 mm in a few spots across higher ground.
14:50pm UPDATE: Electricity supplies could be impacted
Our engineers are busy preparing for #StormAgnes. Strong winds can make it difficult and unsafe for our engineers to work in. If you experience a power cut, we will try our best to get your power back on as soon as it is safe for our engineers to carry out repairs.
Electricity North West said that their engineers are busy preparing ahead of the upcoming storm.
They said: "Strong winds can make it difficult and unsafe for our engineers to work in. If you experience a power cut, we will try our best to get your power back on as soon as it is safe for our engineers to carry out repairs."
Blackburn with Darwen Council has shared advice on how to prepare for an outage.
The council said there was "no need to panic" but said it was a "good idea" to be prepared.
13:52pm UPDATE: Rail services in England issue warnings of disruption
🍃 Due to forecasted strong winds this afternoon, our services between the North West of England and Scotland may be affected.
ℹ️ We are working to understand what the impact will be and will provide more updates as soon as we can. pic.twitter.com/DNiJSDGU3C
Transpennine Express has warned that some of their services may be disrupted because of the storm.
Network Rail Scotland has also told commuters that because of the storm, speed restrictions have been put in place on some routes.
Network Rail also warned of commuter chaos because of the storm.
They said: "Strong winds can blow objects and trees onto the tracks and overhead line equipment. Heavy rain can lead to water blocking the lines."
13:43pm UPDATE: Thousands of homes in Ireland left without power
Thousands of homes and businesses are without power as the effects of Storm Agnes are felt across the country. The South and South East are the worst affected and our correspondent Joe Mag Raollaigh is in Courtown, Co Wexford with the latest | Read more: https://t.co/vBtEuTGLLHpic.twitter.com/pGuDG62ydl
Ofgem, the Government regulator for gas and electricity markets, has warned residents that power and energy services may be disrupted because of the storm.
The regulator says the storm is set to bring in bad weather.
They provided the numbers of services to use if residents experience a power cut or smell gas.
11:30am UPDATE: Met Office updates weather warning
Four weather warnings are currently in place
The Met Office has updated their weather warnings on the storm as it moves closer to Britain.
They said: "As the confidence in the track of Agnes increases, the area of strongest winds has been refined by trimming out parts of northwest Scotland, and also by reducing the southeastern extent across England."
There are now four weather warnings across the UK.
This includes one for wind covering the majority of the UK and three for rain, one being for Northern Ireland and the other two for Scotland.