Latest: Parts of the country still have no power tonight.
They include areas in Counties Kerry, Cork, Limerick and Clare, Wicklow, Meath and Dublin.
They include areas in Counties Cork, Limerick, Clare, Offaly, Wicklow, Wexford and Dublin.
The ESB is aiming to have faults repaired this evening, to thousands of its customers without power.
The River Slaney has overflown its banks in Enniscorthy, Co. Wicklow, where a number of quays are closed.
The N11 which goes through the town has been flooded and there are diversions in place.
In Waterford, there is spot flooding at Carroll's Cross and on some secondary roads.
The River Clodagh in Portlaw is very high with a number of roads into the town nearly impassible as water overflows from the river.
There are hundreds of power outages in parts of the country.
ESB Networks have reported a large fault in the Glengarriff area of Cork while other parts of Cork without power include Castletownbere, Clonakilty, Macroom and Mitchelstown.
They include Nenagh in County Tipperary, along with parts of County Kerry - including Milltown and Killeenleagh.
Dungarvan in County Waterford is also affected along with Athea in County Limerick and Ennis in Clare.
Drumshambo in Leitrim is also without power along with Dundalk in Louth, Navan in Meath and parts of Counties Wicklow and Wexford.
The ESB has said it is a routine winter's day and it remains on alert but is not anticipating a massive level of outages.
They said their crews are mobilised and should have faults repaired this evening.
Derry City and Strabane District Council in Northern Ireland said it had temporarily closed its Winterland market in Guildhall Square in Derry this afternoon, due to "exceptionally high winds and poor weather conditions".
The PSNI urged drivers to take care when out on the roads.
It added: "Strong winds and surface water are making driving conditions hazardous."
Rainfall in Co Down was particularly heavy, with some cars stranded by flooded roads near Ballynahinch.
A Status Orange wind warning has taken effect this afternoon, as Storm Deirdre is due to bring severe gusts potentially reaching 130km/h and heavy rain of up to 50mm.
Met Eireann revised the warning earlier, changing the initial time at which it takes effect from 3pm to 2pm.
The forecaster says that Storm Deirdre will move quickly across the country this afternoon and evening and will move through the Irish Sea early tonight.
The storm will bring some "squally, damaging winds in all areas for a short period of time".
In Munster and Connacht winds will peak mid to late afternoon, depending on location and in Leinster and Ulster in the early evening, Met Eireann said.
Here's the 24 hour rainfall totals to 9am this morning, plus the latest rainfall radar image (11:40am).December 15, 2018
Waterford, Cork, Carlow and Kilkenny are among a number of counties where spot flooding has been reported on the roads.
ESB crews are on stand-by to tackle damage caused by the wet and windy conditions, while a large fault has been reported in the Glengarriff area of Cork.
Thousands are now without power across the country as faults have also been reported in Baltrasna, Co Meath, Telaydon, Co Monaghan, Rathdrum, Co Wicklow, and in Grange, Co Dublin.
Meanwhile, the public has been asked to take precautions when visiting national parks today.
The National Parks & Wildlife Service (NPWS) of the Department of Culture, Heritage and the Gaeltacht have warned that dangerous wind speeds will pose a risk of falling branches and wind-blown debris.
They have asked people to avoid visiting Killarney National Park, and said they will provide further updates as the forecast becomes clearer.
Heavy rain and gale force winds are expected across large parts of the country as Storm Deirdre sweeps in for one of the last big shopping days before Christmas.
Met Éireann named an area of westwards-moving low pressure Storm Deirdre last night.
It has issued a Status Orange wind alert for the entirety of Ireland, warning of "disruptive and damaging gusts" of up 130km/h and persistent and heavy rain.
The warning is in place from 3pm until midnight as the storm tracks northeast over Ireland this afternoon and evening, and motorists are being warned to take care on the roads today.
Rain will become widespread, with some heavy, possibly thundery falls at times in parts of the south and west especially and local spot flooding.
Heavy rain at times in all areas on Saturday & becoming very windy with potentially damaging squally winds in western & southern counties in the late afternoon & these severe winds transferring eastwards during the evening.
For all warnings please see https://t.co/oOxITrsnvw— Met Éireann (@MetEireann) December 14, 2018
Met Éireann says that "severe winds" will transfer to northern and eastern counties this evening after developing in Munster and Connacht in the afternoon.
The rain will clear to showers overnight, with the winds abating and temperatures dropping, leading to frost in some areas.
It will be cold on Sunday, with rain or hail showers in the morning.
The UK's Met Office has issued a series of warnings, with a yellow warning of heavy rain and strong winds up to 110km/h is in place for Northern Ireland, south-west England and South Wales until 6pm.