A red weather alert is in place for the entire country with Hurricane Ophelia is forecast to track directly over Ireland during the day
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.
Also heavy rain and storm surges along some coasts will result in flooding.
There is potential risk to lives.
Met Eireann Meteorologist, Evelyn Cusack says the storm centre is passing directly over the country:
All schools and colleges across the country will be closed today.The Department of Education has informed all schools, colleges and other education institutions that they are to remain closed in response to the approaching Ex-hurricane Ophelia.
The decision was made on advice from the Task Force on Emergency planning and Met Eireann.
Bus Eireann has cancelled all services until 2pm while Dublin Bus says there may be disruptions to some routes.
Irish Rail says there will be NO services on Limerick Junction to Waterford, or Limerick to Ballybrophy via Nenagh - with speed restrictions in place on other routes. Teams will be monitoring the network throughout the storm and customers can follow @irishrail on twitter.
Airports are open but there are cancellations and passengers should check with their airline before travelling.
RSA Communications Manager Brian Farrell has this advice for anyone who has to venture out:
The HSE says all hospital outpatient appointments are being cancelled. Only urgent procedures will take place and only essential community services will operate.
Nearly all courts are cancelled - with local arrangements being made for any custody hearings which must go ahead.
Department of Employment and social protection says all customer appointments are cancelled - but there will be no impact on customer payments.
Driving Test Centres will remain closed today.
Members of the Defence Forces have been deployed to Cork and Kerry in preparation for the severe conditions expected.
In Waterford the Coastguard has asked residents to heed the weather warnings and stay away from the coast.
Clare County Council says it's important to take the red alert warning seriously and is warning locals the high winds could cause real damage.
While Mayo County council's crisis team has been activated and they've implemented a level 3 flood response.
