A third of the normal rainfall expected for September has fallen in the space of just 12 hours.
Katesbridge in Co Down took the brunt of the heavy downfalls that drenched Northern Ireland last night, with 30mm in 12 hours, while Killowen in Co Down recorded 23mm of rainfall, the Met Office said.
A severe weather warning was issued by the Met Office, appealing to people to be prepared for another good soaking. It comes after Northern Ireland recorded its wettest ever August.
Met Office forecaster Dave Elliott said: “It’s normal early autumn weather, around half an inch in most places, but your ground is absolutely saturated already — that’s more the problem. The ground isn’t really able to take it.”
Forecasters Meteogroup said no records were broken, but around a third of September’s expected rainfall fell.
“The rain started falling late yesterday afternoon and turned really heavy in the late evening onwards,” forecaster Matthew Dobson said. “After all the record wet weather in the past 6-8 weeks, the soil moisture levels are saturated. You normally expect a bit of relief from that in the summer but at the moment rivers and streams will be running high.
“I don’t think the flooding will be severe but there’s the potential for some fairly big patches on the roads and some local flooding going on as well.
“Across Northern Ireland, it was 25-30mm which is about a third of what you’d expect for this time of the year. It’s not really record breaking but it’s significant.”
Hopes of an Indian summer were raised by Saturday’s glorious weather but were dashed when the relentless rain reappeared.
But there is no need to despair, Mr Dobson promised.
“The rain that fell overnight is beginning to move towards Scotland, there will be more rain and drizzle today but the worst is probably over,” he said.