Heavy downpours in Greater Boston prompted a flash flood warning to be extended until 11:15 p.m. Wednesday, according to the National Weather Service.

The warning was originally issued through 8:30 p.m. It is in effect for Norfolk, Middlesex and Suffolk counties, according to William Babcock, a meteorologist at the weather service in Taunton.

The flooding could result from “spot storms popping up multiple times over the same areas,” said meteorologist Lenore Correia.