Met Eireann has issued a 25-hour Status Orange rainfall warning for the north-west of Ireland.
The alert has been put in place for Donegal, Sligo and Leitrim as torrential rain in these counties poses a risk of river flooding.
The severe weather warning kicked in at 11am on Sunday and it will be valid until 12pm on Monday.
A spokesman said: "Further heavy persistent rainfall (an additional 50 to 60mm possible) may lead to river flooding and localised spot flooding."
A wind warning for these three counties, as well as Mayo and Galway, is also in place until 10pm on Sunday.
The spokesman said: "Westerly winds with mean speeds of 50 to 60km/h will gust up to 100km/h."
Meanwhile, Met Eireann has warned torrential rain will lash parts of the country at times, posing a risk of "flash flooding" in some areas.
The downpours are expected to be worst in Donegal, Leitrim, Mayo and Sligo, where up to 60mm of rain was forecast to fall between yesterday and today.
Highest temperatures nationwide aren't predicted to surpass 13C apart from places in the south during sunny spells.
There will be "heavy bursts" of rain at times while winds could reach gale force along coasts later on.
The spokesman said: "Windy today with showers or longer spells of rain affecting the northern half of the country.
"There will be heavier bursts at times, bringing a risk of spot flooding mostly in the northwest.
"Elsewhere, predominantly dry with some bright spells and just a few passing blustery heavy showers.
"Maximum temperatures of 11 to 13 degrees generally, rising to between 14 and 16 degrees in any bright spells in the south, with fresh to strong west to southwest winds reaching near gale to gale force at t
