Northern Ireland faces a weather warning for heavy rain, just days after being hit by stormy winds caused by ex-Hurricane Ophelia.
Both the Met Office and Irish national weather service, Met Éireann, have issued warnings.
The Met Office said downpours are expected between 15:00 BST and 23:55.
Flooding is likely and "a few properties or businesses could also be affected", it added.
The yellow warning, which means be aware, has been issued for all six counties.
The Met Office expects 20-40mm of rain to fall within 12 hours on Thursday, although as much as 60mm of rain could fall over the Mournes.
"This will fall on to saturated ground and is likely to lead to flooding in places; delayed travel may well result, including through the busy evening period," it said.
In the Republic of Ireland, Met Éireann has officially named weather conditions for this weekend Storm Brian.
Brian is the second named storm of the British and Irish winter season.
Met Éireann issued an orange wind warning for some coastal counties for Saturday, and a yellow wind warning for the rest of the country.
However, the head of the Irish National Emergency Coordination Group has told RTÉ he does not expect Saturday's storm to be as damaging as Ophelia.
Forecast by Angie Phillips, BBC News NI broadcast meteorologist
The rain will spread east through the morning, becoming increasingly persistent and heavy, especially later in the afternoon and into the evening.
It is likely there will be some localised flooding and travel disruption.
Conditions will be pretty unpleasant for the evening rush hour with further heavy rain.
The rain will eventually move away overnight, when it will become drier with clear spells.
Schools closed on Monday and Tuesday and more than 50,000 Northern Ireland customers were left without power because of the stormy weather created by ex-Hurricane Ophelia.
NIE said most customers should have their power restored by Thursday.
In the Republic of Ireland, three people were killed due to the extreme conditions and more than 350,000 customers lost power.