The Met Office has issued a Yellow weather warning for rain for Northern Ireland tomorrow.
According to the Met Office website a second Yellow weather warning for rain has been issued for Saturday (October 21).
Tomorrow the heavy rainfall will start around 3pm and last until 11.55pm.
"Heavy rain will affect Northern Ireland later on Thursday," said the Met Office.
"This will fall onto saturated ground and is likely to lead to flooding in places; delayed travel may well result, including through the busy evening period.
"It is possible that a few properties or businesses could also be affected."
According to the Chief Forecaster, "rain will spread into Northern Ireland on Thursday morning, turning persistent and occasionally heavy in the afternoon and lasting well into the evening before dying out".
He added: "20 to 40 mm of rain within 12 hours, (perhaps nearer 60 mm over the Mournes) falling on already very wet ground, seems likely to lead to flooding of some prone locations."
Meanwhile, on Saturday, the weather warning has been forecast for between 4am and 11.59pm.
A spokesman for the Met Office said: "A spell of strong southwesterly winds is expected.
"Some coastal routes and communities are likely to be affected by large waves, with potential for flooding of properties. Some transport disruption is likely across the warning area, with delays to road, rail, air and ferry transport.
"Short term loss of power and other services is also possible."