Hurricane Ophelia is set to pummel the UK and Ireland with winds of up to 80 mph and cause "potential risk to lives", the Met Office has warned, even as the storm weakens to a Category 1 hurricane.

Ophelia churned across the Atlantic from the Azores towards the UK and hit County Kerry early Monday with hurricane-force winds.

The post-tropical cyclone had intensified over the weekend, making it the farthest east Category 3 hurricane on record for the Atlantic Basin, before weakening and making landfall.

All schools in Ireland are closed for the day and motorists and cyclists have been warned to stay off the roads.

Ireland's Taoiseach Leo Varadkar has sent defence forces to areas like Wexford, Galway and Limerick.

He tweeted: "Defence forces being deployed in Red weather alert areas and on standby for further action (on Monday).

"Please check in with older neighbours and those who need medical care."

In pictures: Storm Doris hits the UK Show all 17 1 /17 In pictures: Storm Doris hits the UK In pictures: Storm Doris hits the UK A fallen tree brought down by high winds from Storm Doris lies across a main road in Isleworth in London, Britain Reuters In pictures: Storm Doris hits the UK Emergency personnel attend the scene in Cardinal Place, Victoria aftera man is thought to have been injured by a section of falling debris PA wire In pictures: Storm Doris hits the UK Commuters waiting at King's Cross Station in London, as flights have been cancelled and commuters were warned they faced delays after Storm Doris reached nearly 90mph on its way to batter Britain. PA wire In pictures: Storm Doris hits the UK A bin blown onto the tracks at Waterloo station in London, as flights have been cancelled and commuters were warned they faced delays after Storm Doris reached nearly 90mph on its way to batter Britain PA wire In pictures: Storm Doris hits the UK A car damaged by a tree which left two men injured, on the A49 north of Church Stretton in Shropshire PA wire In pictures: Storm Doris hits the UK The scene in Wolverhampton city center after a woman died when she was hit by a piece of roof the 'size of a coffee table' as Storm Doris has claimed its first victim PA wire In pictures: Storm Doris hits the UK A double decker bus blown onto its side by Storm Doris in Walton Highway near Wisbech, Cambridgeshire, as flights have been cancelled and commuters were warned they faced delays after Storm Doris reached nearly 90mph on its way to batter Britain PA wire In pictures: Storm Doris hits the UK A double decker bus blown onto its side by Storm Doris in Walton Highway near Wisbech, Cambridgeshire PA wire In pictures: Storm Doris hits the UK Spikes protude from a colourful umbrella as a woman struggles against the elements on the seafront at Seaham, in County Durham, north east England EPA In pictures: Storm Doris hits the UK ESB workers attend to power lines damaged by a fallen tree as allmost 46,000 Irish households woke up to no electricity after violent gusts battered large swathes of the country through the night PA wire In pictures: Storm Doris hits the UK A children's play area is crushed by fallen trees in Stoke-on Trent, as Storm Doris battered swathes of the country PA wire In pictures: Storm Doris hits the UK A plane comes in to land at Leeds Bradford Airport as flights have been cancelled and commuters were warned they faced delays after Storm Doris reached nearly 90mph on its way to batter Britain PA wire In pictures: Storm Doris hits the UK People make their way across Westminster Bridge while gusts of winds sweep across the capital in London EPA In pictures: Storm Doris hits the UK Queues outside Peterborough railway station after Storm Doris reached nearly 90mph on its way to batter Britain PA wire In pictures: Storm Doris hits the UK A tree which has fallen onto a van in St Anne's Road in Aigburth, Liverpool, as Storm Doris battered swathes of the country PA wire In pictures: Storm Doris hits the UK A rainbow over the Nottingham Wheel in the Old Market Square, as Storm Doris reached nearly 90mph on its way to batter Britain PA wire In pictures: Storm Doris hits the UK Waves crash over the lighthouse in Newhaven, East Sussex PA

Aer Lingus has cancelled a number of flights due to the severe weather, while Ryanair and Loganair advised passengers to check their websites for updates.

While the storm may have lost its tropical characteristics due to colder sea-surface temperatures nearer Ireland, its wind field is expected to expand, meaning areas farther from the centre of the storm will be impacted.

Met Eirann has issued a red wind warning for all of Ireland on Monday for sustained winds of more than 50 mph and gusts of up to 80 mph, which could cause structural damage, down trees and power lines.

"Violent and destructive gusts are forecast with all areas at risk and in particular the southwest and south in the morning, and eastern counties in the afternoon,” the warning read. “Also heavy rain and storm surges along some coasts will result in flooding.

"There is potential risk to lives."

The UK Met Office issued an amber wind warning in Northern Ireland. The office indicated possible transport delays but no power outages.

“Flying debris is likely, such as tiles blown from roofs, as well as large waves around coastal districts with beach material being thrown onto coastal roads, sea fronts and properties,” it read. “This leads to the potential for injuries and danger to life.”

The Met Office issued a yellow warning for wind across western Scotland, Wales and far western England.

Before Ophelia, Hurricane Frances was the farthest east Category 3 hurricane in the Atlantic Basin in 1980.

Some experts have compared Ophelia to Hurricane Debbie in 1961, which killed 12 people in Ireland.

The UK Military of Defence (MOD) has 1,200 soldiers permanently on standby to assist with emergencies.

An MOD spokesman said it has not yet received requests from local authorities.