Rain is expected to linger through mid-week after causing flooding in areas south and west of Pittsburgh on Sunday.
While only .08 inches of rain was measured at Pittsburgh International Airport as of early Sunday evening, up to 2-to-3 inches fell in parts of Washington County, National Weather Service meteorologist Colton Milcarek said.
In Washington County, there were reports of a number of roads being washed out and water running over roads and getting into some homes, he said.
Here’s a look at where estimated rain totals sit from the last 24 hours: pic.twitter.com/8dxAM6wc70
— NWS Pittsburgh (@NWSPittsburgh) September 20, 2026
Widespread rain is expected overnight Sunday into Monday morning. A flood watch for flash flooding covering southwest Pennsylvania is in effect until Monday.
The forecast has a chance of rain through Wednesday and possibly into Thursday before tapering off, Milcarek said. Areas that have already seen significant rainfall would be most at-risk for flooding.
The extended outlook is for the region to dry out late Thursday into Friday, with very low chances of rain Friday through Sunday, Milcarek said.
Autumn officially arrives at 8:05 p.m. Tuesday. High temperatures the next couple of days will be in the mid-60s, a little below the normal of the low-70s, before warming to near normal by Sunday.