The Met Office has issued a yellow status severe weather warning of rain for Northern Ireland.
The alert was issued on Wednesday morning and is valid for the entirety of Friday August 9, 2019.
"A band of heavy rain, with the possibility of some very heavy bursts, will move northwards during Thursday night and Friday," reads the warning on the Met Office website.
"Within this band 10-15 mm is widely expected, however some places could see as much as 30 mm in just a few hours.
"Once the rain has cleared scattered showers and thunderstorms are expected to develop, particularly during Friday.
"Many places will miss these, but where they do occur 10-20 mm is possible in one hour, with perhaps 30 mm in a few hours."
The weather alert applies to the whole of Northern Ireland
What to expect
There is a small chance that homes and businesses could be flooded, causing damage to some buildings.
There is a small chance of fast flowing or deep floodwater causing danger to life.
Where flooding occurs, there is a slight chance of delays or cancellations to train and bus services.
Spray and flooding could lead to difficult driving conditions and some road closures.
There is a small chance that some communities become cut off by flooded roads.
(Source: The Met Office)