A Met Office weather warning is in place regard heavy rain across Northern Ireland this morning, falling as snow over some of the higher ground.
The forecaster says Storm Doris has the potential to lead to some travel disruption and localised flooding.
Rainfall totals of 20-40 mm are expected across the area.
The warning is in place until 2pm today, Thursday and care is advised especially for high sided vehicles.
Traffic Watch NI warned of a tree down on the Ballykeel Road near the bridge 100 metres south of the Old Newry Road in Co Down
and that the A509 Derrylin Rd is partly blocked but passable a mile north of Bellanaleck in the direction of Enniskillen.
It also advised of a tree down at Derrylecagh Row (Coopers Hill) and for caution coming from Mayobridge to Newr.
The storm has reached nearly 90mph on its way to batter Britain as flights have been cancelled and commuters were warned they faced delays.
Doris is likely to damage buildings and send debris flying when it sets in at around 6am on Thursday, the Met Office has said.
An 87mph gust was recorded at Mace Head on the Galway coast in the Republic of Ireland in the early hours as Doris made its way east.
The UK was being battered by gales in the early hours, with speeds of 72mph recorded at Aberdaron on the west coast of Wales.
Met Office meteorologist Mark Wilson said: “Winds are really starting to pick up now, mainly across western parts of the country.”
Aer Lingus cancelled 12 flights between the UK and the Republic of Ireland in anticipation of the winds and Heathrow Airport warned customers to check their flights before travelling.
Network Rail warned of delays and cancellations after imposing speed restrictions for safety reasons.
Limits of 50mph would be observed on some services run by Southeastern, Arriva Trains Wales, Chiltern Railways, Grand Central, TransPennine Express and Virgin Trains East Coast.
Britain is expected to be battered with winds of up to 80mph at the storm’s peak and Highways England has issued a weather alert on major roads.
Particularly at risk are high-sided vehicles, caravans and motorbikes and drivers are “strongly advised” to avoid travelling on some stretches of road in Yorkshire, the Midlands, and the East and North West.
Richard Leonard, head of road safety at Highways England, said: “We’re expecting Storm Doris to have a significant impact on the roads throughout the day so are urging drivers to consider changing their plans if necessary and to slow down in stormy weather.
“Drivers should look out for warnings on the electronic message signs and listen for updates in radio travel bulletins.”
Amber warnings predict strong winds and heavy rain in parts of north Wales, the Midlands, and the East and North West, while winds as fast as 60mph are also expected to batter southern England.
Meanwhile, up to 15cm of snow could fall across parts of Scotland and north-east England in treacherous, blizzard-like conditions.
Weather warnings have been upgraded to amber across Scotland’s central belt, the Borders, Dumfries and Galloway, Tayside and Fife.
“We have got a fairly active area of low pressure coming in from the Atlantic,” said Met Office forecaster Emma Sharples.
“It is strengthening as it moves eastwards to the UK.”
The Met Office’s amber weather warning alerts people that “whilst the strongest winds look to be only short-lived, damage to structures, interruptions to power supplies and widespread disruption to travel networks are likely, with a danger of injury from flying debris”.
Storm Doris is expected to move on quickly, with the worst of the weather gone by Thursday evening.
While further Atlantic gusts will bring more rain and wind through the weekend and into next week, they are not expected to reach the heights of Doris.
AA spokesman John Snowling said: “The unpleasant combination of torrential rain, severe gales and heavy snow will create some very poor driving conditions, with the potential for roads to be affected by black ice, debris or standing water.
“Wind can also bring down tree branches, blow you off course or blow other vehicles into your path.
“Expect travel disruption as some roads will be treacherous.”
Anyone affected by power cuts during the storm is encouraged to dial 105 for further information.
Storm Doris’s appearance contrasts with Monday’s temperatures, where visitors to Kew Gardens, west London, enjoyed the warmest day of the winter so far, at 18.3C (64.9F).
Parts of London and the South had temperatures warmer than Ibiza, southern Spain and Menorca.
Dozens of flights into and out of Heathrow Airport are expected to be cancelled, with other passengers likely to experience delays.
A Heathrow spokesman said: “Strong winds and poor weather across the UK have resulted in approximately a 10% reduction to Heathrow’s flight schedule.
“With Heathrow operating at more than 99% capacity, there are no gaps in the schedule that can be used for delayed flights and as a result, some passengers may experience disruption to their journeys today.”