Met Éireann has upgraded weather warnings to status red, the most severe level, for six counties ahead of Storm Darragh.
The national forecaster has warned of "extremely strong and gusty northwest winds" for counties Donegal, Leitrim, Sligo, Clare, Galway and Mayo.
The red warning is in place until 2am on Saturday morning for Clare and Galway, and 3am for Donegal, Leitrim, Sligo and Mayo.
There was already a status orange wind warning for the whole country.
The entire country will be subject to a status orange wind warning from 10pm tonight.
It will apply to Munster and Connacht from 8pm this evening, and run until 10am in the morning.
The national forecaster said Storm Darragh will bring very strong and gusty northwest winds.
Met Éireann has also warned the strom will bring fallen trees, damage to power lines, "very difficult" travelling conditions, damage to temporary structures and wave overtopping.
A Met Éireann spokesperson said: "Storm Darragh will bring very wet and windy weather today. Rain will spread across the country from the west and will be heavy at times, possibly causing localised flooding.
"Some sleet is possible on northern hills and there is a chance of isolated thunderstorms. Strong and gusty south to southeast winds will develop through the morning and will become very strong and gusty south to southwest in the afternoon and evening. Highest temperatures of 8 to 13 degrees."
The National Directorate for Fire and Emergency Management met this morning on the incoming storm, and will come together again this afternoon.
The group's Keith Leonard expects organised Christmas events, like markets, to be cancelled.
Mr Leonard said: "We're going to have a lot of people out, maybe having Christmas parties and socialising tonight as well, and they just have to be very aware of the weather conditions.
"Where possible, postpone those celebrations until a later date because it will be very unpleasent and very dangerous and difficult across the country."
Concern has been raised over asylum seekers sleeping in tents in Dublin city centre as Storm Darragh approaches.
Dozens of tents were erected on an open square beside the Department of Agriculture on Kildare Street on Thursday, less than 100 metres from an entrance to the grounds of Leinster House.
The Irish Refugee Council said some of these people had been accommodated indoors in the CityWest accommodation centre in recent days but have since been forced to sleep rough.
