Local residents have been warned of the potential for localised flooding today (Wednesday).
The Met Office has issued a severe weather warning, lasting until 11pm this evening as further rain is forecast.
As the low pressure system is travelling eastwards across Northern Ireland, County Down and County Antrim will become increasingly affected into the evening.
“A complex area of low pressure moving across Ireland today will bring further outbreaks of rain, perhaps accompanied by thunder, across Northern Ireland this afternoon and evening,” said the Met Office.
“Rain is expected to be heavy at times with some local downpours possible. Overall totals between 20 and 40 mm in 3 to 6 hours are possible, although some areas will receive less than this.
“The heaviest rain is expected to be over western regions this afternoon and then over eastern regions this evening.”
As the rain subsides though, it will give way to a much drier weekend ahead, even if the sun will only peak through the clouds in sparing intervals. Temperatures are set to remain at highs in the mid-teens.