May 24, 2021
A quasi-stationary boundary was in place over southwest Pennsylvania on May 24th. Taking advantage of an abundance of moisture and upper shortwave support, showers and thunderstorms developed and tracked along the boundary. A couple of flooding events occurred in the urbanized areas of Allegheny County.
Source: NOAA National Weather Service Storm Events Database (event 957746). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Allegheny County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.