Met Éireann has issued warnings about high Atlantic waves and gusts of up to 120km/h for today.
Parts of Galway city suffered flooding this afternoon after almost 1cm of rain fell in two hours.
Fire Brigade and city council employees are working to clear drains and gullies after a number of businesses along Flood Street and Spanish Parade flooded.
Cross Street in the city remains closed pending a clean-up of the area.
Forecasters said there will be “exceptionally high waves” on Atlantic coasts today. As a result there is a threat of coastal flooding, particularly at high tide, with waves of up to 9m, Met Éireann said.
Winds on the Atlantic coast will reach speeds of up to 75km/h with gusts of up to 120km with the strongest winds will be along the west coast.
There will also be winds of between 45km/h and 60km/h in other areas of the State with gusts of 70km/h to 90km/h.
Winds and rainfall have caused problems for motorists in many areas. Routes in Galway city on Wolfe Tone Bridge, Flood St and Lough Atalia Rd are impassable following substantial rainfall, AA Roadwatch said.
In Cork city a fallen tree has blocked traffic on the Lee Road. In Kildare a fallen tree is blocking the Monasterevin/Athy Rd and as it is on a dangerous bend care is required, AA Roadwatch said
There is "very big surf in Bundoran this morning", Irish big wave surfer Richie Fitzgerald wrote on Twitter.
The Road Safety Authority said a combination of high tides, storm surge and winds may result in a risk of localised flooding. It has urged drivers to in wet and windy conditions to allow extra space between cars, to watch for falling debris and cross winds, to be aware of aquaplaning, to drive with dipped headlights.
Irish Water Safety is warning the public of the increased risk to drowning around the coastline for the next few days. 10 per cent of all recorded drowning in the State are as a result of people walking close to the waters edge, chief executive John Leech said.