Met Éireann has issued a Status Orange rain warning for several counties in the east of the country today (Monday, July 21).
The national forecaster said there will be persistent and heavy rain with a chance of thunderstorms across Dublin, Louth, Meath and Wicklow.
The warning, which came into force at midnight, is due to remain in place until 2:00p.m today.
The conditions will bring a risk of widespread surface flooding; very difficult travelling conditions; lightning damage, along with very poor visibility.
A Status Yellow warning for spells of heavy rain with a chance of isolated thunderstorms has also been issued for Kildare and Monaghan.
The warning, which may lead to localised flooding, poor visibility and difficult travelling conditions, is valid until 2:00p.m.
The UK Met Office has issued a Status Orange rainfall warning for Antrim, Armagh, and Down where there could be flooding.
The warning will be replaced by a Status Yellow warning this morning which will remain in place until 6:00p.m today.
Met Éireann said that today will be wet across Leinster and east Ulster, with drier conditions and isolated showers elsewhere.
During the late afternoon, the rain in the east will turn patchy. Highest afternoon temperatures of 15° to 20°C in moderate, occasionally fresh, north-west breezes.
Tonight will be largely dry with clear spells and some isolated showers. The west to north-west winds will be light, with lowest temperatures of 11° to 14°.
Tuesday morning will be mainly dry with some isolated showers but more frequent showers will push in from the west during the day.
Highest temperatures of 15° to 19° in a light to moderate west to north-west wind.
Met Éireann has said that the current outlook is for drier weather for the rest of the week, with rainfall accumulations expected to be small.
Showers will become more isolated on Tuesday night with dry conditions and clear spells in many areas. Overnight lows of 10° to 14° in a light north-westerly breeze.
Wednesday will be a cloudy day, it will be mainly dry with some isolated showers. The north-west winds will be moderate with highest temperatures of 15° to 19°.
Mainly dry with clear spells on Wednesday night, with cloud building towards morning. Lowest temperatures of 9° to 13° with light to moderate northwest breezes.
Thursday will be dry and cloudy in many parts of the country, some isolated showers are possible. Rain and drizzle will arrive in the west and south-west in the evening.
Highest temperatures of 18° to 22° in light to moderate north-west winds veering west to south-west.
Cloudy on Friday morning with scattered showers. The showers will become more isolated with sunny spells developing later in the day. Highest temperatures of 16° to 20° in moderate, occasionally fresh, westerly winds.
The current outlook is for dry weather on Saturday with sunny spells and showers. Sunday may see more persistent rain.