Householders and motorists have been warned to expect flash flooding during heavy rainfall along the east of the country. Southern counties will also see heavy rain.
Met Eireann has forecast 25mm of rain could fall over a 12-hour period from 9am.
AA Roadwatch appealed to motorists to drive through water only if they know it is not too deep for their car.
Elsewhere Dublin City Council said resources are on standby to attend to flood locations that may arise.
It said the predicted rainfall is considerably less than last October, when 100mm fell in 24 hours, flooding hundreds of homes and cars and leaving two people dead.
“Gullies and river screens in flood-prone areas are being cleaned and monitored during the warning period,” it said.
“The city council will have a stock of sandbags placed on standby for strategic deployment.
“Owners of premises that consider themselves at risk of flooding are also advised to make provision to defend their own premises.”
It warned that because extreme rainfall events are unpredictable, all parts of the city could be prone to flooding.
“While there is no threat of tidal flooding, the city council, as an additional reassurance to residents in the lower Dodder area, will close the tidal gates at this location,” it added.
Gardaí also called on motorists to allow extra time for any journeys and take all necessary precautions.
“As driving conditions are expected to be challenging, possible local flooding, we are asking motorists to reduce their speed,” a spokesman added.