Roads and public transport have been disrupted after heavy downpours of rain, lightning and thunder over the eastern half of the country.
Motorists have been warned of surface water and spot flooding.
AA Roadwatch said that roads in Dublin were among those affected, including parts of the M50.
There was also disruption to Dublin Connolly-Maynooth and Docklands-M3 Parkway rail services after signalling was damaged by lightning.
Iarnród Éireann has said that services are returning to normal.
Services on the Luas Green Line in Dublin are operating between Brides Glenn and Parnell stops only.
There are no trams between Broombridge and Dominick.
A Luas spokesperson said: "technicans have been working since early this morning to resolve the issue as quickly and safely as possible.
"However, service is not expected to resume between Broombridge and Dominick for the rest of the day".
Met Éireann said that more than 22 millimetres of rain was recorded over a five-hour period in the Phoenix Park in Dublin this afternoon.
The forecaster said that heavy showers and thunderstorms in the east of the country, giving torrential downpours and localised surface flooding, cleared tonight as drier and clearer weather extended from the west.
Update: Maynooth/M3/Sligo services are now expected to depart and operate to schedule following earlier signalling issues caused by lightning— Iarnród Éireann (@IrishRail) July 30, 2019
Green Line update: Service is not expected to resume between Broombridge and Dominick for the rest of the day. Please see https://t.co/GkL4FmFo1J for further information. Tickets are valid on Dublin Bus.— Luas (@Luas) July 30, 2019
Dublin Fire Brigade said it was called out to a number of locations in the city this afternoon after lightning and heavy rain.
The National Gallery of Ireland on Dublin's Merrion Square was forced to close this afternoon as a result of flooding.
In a statement it said: "Today's sudden rainfall resulted in flooding in two of the gallery's back of house staff areas. As a precautionary measure the gallery has closed this afternoon. It will reopen tomorrow."
None of the public areas of the gallery were affected.