There are 50,000 homes, farms and businesses currently without power as ESB crews continue to work to reconnect premises across the country.
Power has already been restored to more than 140,000 homes and businesses since this morning.
While ESB crews continue to work into the night to repair damage caused by Storm Ellen, the ESB said some customers in areas of the South, West and Midlands will remain without power tonight.
The storm has caused widespread damage with Cork, Tipperary, Sligo, Westmeath, Longford, Galway, Roscommon and Leitrim the worst impacted.
The damage is mainly attributable to fallen trees on overhead lines as a result of the high winds.
A statement said: "We are advising all those impacted by outages that they should prepare to be without electricity overnight and into tomorrow, with small pockets of customers potentially without power beyond that.
"It is very important that any customers who use electrically powered medical devices should contact their healthcare professional to make alternative arrangements if necessary."
ESB crews from less impacted areas of the country are mobilising to assist colleagues in repairing damage in the most impacted areas.
At its worst there were 194,000 premises without power with Cork, Tipperary and Limerick the worst affected.
Derek Hynes of ESB Networks said: "We are asking everyone to stay safe. We are worried about families going for a walk, about children playing."
People are reminded not to approach or touch fallen trees, wires or damaged electricity networks as they may be live and extremely dangerous.
There is currently a Status Yellow rainfall warning in place for the entire country until 5am tomorrow morning, while a Status Yellow wind warning comes into effect from 5pm for Cork, Kerry, Waterford, Dublin, Louth, Wexford, Wicklow and Meath, until 5am tomorrow.
Met Éireann said there will be heavy showers today and tonight with a risk of thunderstorms and spot flooding.
There will be strong and gusty southerly winds which will reach up to gale force at times in coastal areas.
There is also a wind warning in place for Carlow and Kilkenny in place from 10pm until 11.59pm tonight.
Met Éireann said that “very strong southerly winds with some damaging gusts will result in disruption in places”.
It said Storm Ellen broke Mean Wind Speed and MSL Pressure records for the month of August, and warned that as our climate continues to change we can expect more weather records to be broken.
#StormEllen broke Mean Wind Speed (111 km/h) & MSL Pressure (966.4 hPa) records for August.— Met Éireann (@MetEireann) August 20, 2020
As our climate continues to change we expect more weather records to be broken
Met Éireann Radar images show the passage of Storm Ellen over Irelandhttps://t.co/U8dRywvyWo pic.twitter.com/iPHqrW2piu
Meanwhile, Cork city has seen flooding due to high tide.
The city council said that one minute after high tide, "Morrison’s Island breached".
There has also been reports of flooding on Wandesford Quay and on Union Quay in the city.