Jul 9, 2025
Convection across southern Pennsylvania began to develop in an unstable and moist environment ahead of a shortwave trough traversing the area during the afternoon and evening hours of July 9, 2025. Storms initially were sub-severe due to lower shear parameters and low-level lapse rates; however, increasing shear and lapse rates allowed for damaging wind potential within an environment of 700-900 J/kg of DCAPE. Shear oriented out of the southwest, parallel to surface boundaries, led to an increas
Source: NOAA National Weather Service Storm Events Database (event 1278557). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in York County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.