UPDATED: 19/10/2020 8.55am
A rainfall warning is now in effect for Munster, Connacht, Donegal, Cavan and Monaghan.
An earlier national alert has been amended with a warning for Leinster to come into effect from 11am this morning.
Met Éireann said persistent and occasionally heavy bands of rain will cross the country, with the warning extending from midnight last night through to Tuesday evening.
There is a risk of localised spot flooding with a heightened risk of flash flooding in mountainous regions where rainfall is expected to be highest.
The warning is valid until 7pm on Tuesday.
Met Éireann said unusually high tides combined with strong winds will create an elevated risk of coastal flooding.
In the North, the UK Met Office has issued a rain warning for counties Armagh, Derry, Down, Fermanagh and Tyrone, with flooding and travel disruption possible.