Rainfall should ease later on Tuesday following an afternoon during which a yellow weather warning was in place across Armagh and Down.
The Met Office warned of train and bus journey times affected, spray and flooding on the roads leading to hazardous conditions and some interruption to power supplies.
Heavy rainfall was reported across both counties, while Belfast also saw regular bursts. The Met Office said some places in the north will record 10-22mm of rainfall over the afternoon with 20-30mm possible in areas. The yellow warning was in place from around 1pm to 5pm.
After a relatively mild, if wet period, the weather will turn colder on Wednesday but brighter with sunny spells and shower. It will be colder again , and colder again on Thursday with maximum daytime temperatures dropping below 10 degrees.
Temperatures could dip to close to freezing overnight on Thursday and continue into Friday morning.