The watch is in effect until 8 a.m. on Wednesday and includes Donegal, Aliquippa, Ambridge, Columbiana, East Liverpool, Monaca, Latrobe, Greensburg, Monessen, Ligonier, Beaver Falls, Murrysville, New Kensington, Salem, and Lower Burrell.
According to the weather service, excessive runoff from precipitation from Monday and today could result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Creeks and streams may rise out of their banks.